Undercover: Murder of Louis H. Dayton 1929

Murder Victim

Louis H. Dayton
a.k.a. Clarence L. Plummer
a.k.a. Bert Cook
a.k.a. Bert Pettit
54-year-old Special Deputy Sheriff

Cause of Death: Beaten with Brass Knuckles
Motive: Revenge for Snitching

Murder Scene and Date

Attacked at Post Office
Died at 426 West Pine Street
Spencer, Iowa
Clay County
End of Watch: March 20, 1929


By Nancy Bowers
Written June 2015

Location of Spencer, Iowa

location of Spencer, Iowa

On the night of March 20, 1929, Emma Jensen lay half-asleep in her house at 426 West Pine in Spencer, staying alert for noises and, as she did every night, monitoring the activities of two roomers who lived upstairs from her and her husband Chris.

One roomer was in bed, but the other — a man she knew as Bert Cook — was not yet home. That was not unusual and did not worry Emma because she realized that his secret work kept him out at all hours of the night.

When Cook came to live with the Jensens three weeks before, he confided in Emma that, although he pretended to be a salesman of a cleaner that removed spots from clothing, he was in fact a Special Deputy working undercover for local authorities.

His job was to gather information on Spencer and Clay County residents who were buying, selling, transporting, or drinking illegal alcohol and thereby breaking Prohibition laws. His covert work would be used to prosecute those individuals. He swore Emma to secrecy; she was not even to tell her husband.

Emma was not concerned about having an undercover agent in the house, even though he was two weeks behind in the rent. He was quiet and well-behaved, at times dressed in overalls and at others in a dark suit. He always greeted her and her husband with a friendly hello and assured her he never touched liquor.

☛ Strange Behavior ☚

from the Muscatine Journal and News Tribune

from the Muscatine
Journal and News Tribune

At 11:00 p.m., Emma Jensen heard Cook come into the house and climb the stairs to his room; he seemed to use the water bowl and pitcher. Then he hurriedly came back down the steps and went out, leaving the hallway lights on and shutting the front door with such force that it bounced back and stayed open.

Emma got out of bed and woke her husband to tell him what happened. When she went to turn off the lights and shut the door, she looked out the living room window and saw Cook briskly walking east towards the downtown area.

About 20 minutes later, he came back a second time and stood on the front porch briefly and then left again. Emma got up once more and saw him walking in the same direction as before.

Not long afterwards, Cook returned a third time and came into the house. Access to the stairway to his room was through the dining room off which the Jensens slept.

He stopped there and called out, “Is this Chris’s place?”

Emma responded, “What is the matter with you?”

☛ Blood and Wounds ☚

Cook stood silently in the dark and then said:

“I feel funny; it seems like I can’t hardly see. It seems like I am half blind. I must have fell or something like that. I’m bleeding.”

Chris and Emma — who felt a chill go through her when she heard those words — both got out of bed. She told Cook to wash up in the kitchen. When she came in to help, the sink was partially filled with blood.

He was making strange noises in his throat and washing his face with a colored bandana. Fearing that the dye in it might be poisonous, Emma gave him a piece of white cloth.

Dazed and wounded, Cook could not say what happened to him. The last he remembered was encountering two men. When he regained consciousness, he was lying on the sidewalk west of the Post Office about two blocks from the Jensens’ home.

Cook looked at himself in a mirror and pointed to a deep wound under his chin and said it appeared that he had been “hooked.”

Emma Jensen later told authorities:

“What he meant by that I don’t know, but from the looks of the wound it seemed that someone must have stabbed him with a sharp instrument and gouged him when it was imbedded in his flesh.”

He thrust his knuckles up against Chris Jensen’s jaw to demonstrate how he was struck.

Louis Dayton, a.k.a. Bert Cook and Clarence Plummer from the Spencer News-Herald

Louis Dayton, a.k.a. Bert Cook and Clarence Plummer (from the Spencer News-Herald)

He said his head hurt and he felt “queer all over” and complained so intensely about chest pain that Chris Jensen, thinking he might have been shot, unbuttoned his shirt but found no wound there.

Eventually, they stopped the flow of blood and Cook said he would be all right and asked Chris to bring a basin of cold water up to his room. He adamantly refused a doctor.

Cook picked up his cap and blood-spotted overcoat and started up the stairs with Chris Jensen following. He opened the door to his room, switched on the light, and then fell across the threshold.

Chris called for Emma. When she got to the room, she and Chris turned Cook over; he gasped and vomited. Emma went down to phone for Dr. T.H. Johnston and when she returned washed Cook’s face with cold water to revive him; however, she could see he had not fainted but was dead. The other roomer, awakened by the commotion, took a look and agreed that Cook was deceased.

Dr. Johnston found the victim lying face up next to the bed with his arms by his sides and his shirt unbuttoned. His face was bluish and there was a cut on the right jaw that went down to the bone. A wound on his nose and two small cuts at the back and upper part of his left ear were bloody.

☛ Authorities Arrive ☚

Clay County Sheriff Fred W. Erickson, County Attorney Claude W. Baldwin, and Coroner J.M. Sokol were summoned to the scene.

Sokol searched the victim’s pockets and found a watch, $3.46, miscellaneous papers, and two photographs. These were given to County Attorney Baldwin, who refused to reveal to newspaper reporters if there were records about local bootleggers in the victim’s possession.

Because the watch and money were not taken, it appeared that robbery was not the motive for the attack.

Based on a preliminary examination, Coroner Sokol said that, although the victim’s skull was not fractured, he likely died from a blood clot on the brain from being struck on the head. That type of injury would account for his muddled and dazed behavior.

After viewing the body, investigators followed a blood trail to a spot 30 feet west of the Post Office, where two large pools stained the sidewalk and marked the place of attack. The blood amounts indicated the victim did not lie on the sidewalk long but tried in his confused state to find the Jensens’ house as soon as he became conscious.

Inquest Surprise: Bert Cook is Clarence Plummer

On Thursday morning, March 21, Coroner J.M. Sokol and County Attorney Claude Baldwin convened a closed-door inquest to gather information on the death. John Smith, E.E. Davis and J.C. O’Brien, all of Spencer, made up the jury. Also present were Spencer Mayor Eugene E. Bender and local law enforcement officers. The inquest continued over to Monday so an autopsy could be placed in the records.

During their testimony before the coroner’s jury, Emma and Chris Jensen learned for the first time that the man who died in their home was known to local authorities as Clarence L. Plummer, not Bert Cook.

Sheriff Fred Erickson testified that he understood the man was C.L. Plummer and had appointed him as Special Deputy Sheriff of Clay County three weeks prior.

☛ Autopsy ☚

from the Spencer News-Herald

from the Spencer News-Herald

An autopsy on Clarence Plummer’s body was conducted by Coroner Sokol, Dr. T.H. Johnston, and Dr. C.C. Collester at 4:00 p.m. on Friday, March 22 in Cobb’s Undertaking Parlors.

Plummer’s knuckles were raw and scratched, indicating he fought back against his attackers. The deep chin wound and bruises on his lips and nose appeared made by brass knuckles. He had small cuts behind the left ear and a dark area about the size of a dime on his scalp.

An examination of the brain revealed a hemorrhagic area. The frontal lobe on the right and left was red and congested. No congestion was visible under the cuts behind the ear, however.

Blood loss from the deep chin wound and the blow to the nose was not enough to have caused death.

The physicians ruled the victim died “from contusions of the brain as the result of a blow on his head.”

With this information from the autopsy, the coroner’s jury issued its verdict on Monday, March 25: Clarence Plummer died from a beating with brass knuckles by a person or persons unknown.

☛ Funeral Services For the Victim ☚

from the Spencer News Herald

from the Spencer News-Herald

On Tuesday, March 26, brief services were conducted for the victim at the Cobb Funeral Home by Dr. Herbert Clegg, pastor of Grace Methodist Church.

Pallbearers were law enforcement officers: County Attorney Claude W. Baldwin, County Sheriff Fred W. Erickson, Deputy H.A. Wilsey, Chief of Police W.H. Jones, Constable Earl Guy, and A.L. Risely, a Deputy Sheriff of Calhoun County.

Two floral displays flanked the coffin — one each from the Calhoun County and Clay County sheriffs’ departments.

The body was placed in the Riverside Cemetery mausoleum; it was to be kept there for two months — in case family members came forward — and then buried at Clay County’s expense.

☛ Investigation Yields Few Clues ☚

County Attorney Claude Baldwin and Sheriff Erickson requested help from the Iowa Bureau of Criminal Investigation (BCI), which sent Special Agents H.C. “Hi” Yackey and Ray Scott to work the case.

Investigators admitted they had little success finding details on the assault.

The Spencer Reporter wrote about the perplexing lack of witnesses:

“Occurring on Wednesday night within a block of Main Street and with a crowd of hundreds in town for the weekly dance, the attack is described as the boldest ever attempted here. How long he lay unconscious on the sidewalk is not known, but no one has been found who saw him there, although the north side of the street was lined with cars and the scene of the tragedy was in full view of more than a score of rooms in the Tangney Hotel.”

 Spencer News-Herald

from the Spencer News-Herald

About 9:30 p.m., Mrs. Nelson Butterworth who lived at the southeast corner of the Floete Apartments close to the crime scene, heard fighting in the alley by the Post Office and looked out her window. A group of males was trying to force someone into a car, she said, and blows were struck. When she yelled at them the victim ran away, but they caught him again. She speculated it was high school boys trying to take an underclassman for a ride into the country to leave him to walk home.

Clara M. Hoenk, who lived on the second floor of the same building, heard and saw a group of men about 10:30 but observed no fighting. A ginger ale bottle was found near the sidewalk at that spot.

Because Plummer was attacked so close to the downtown business district, authorities assumed the assailants had not intended to kill him, but only to send an intimidating message, which was why brass knuckles were used rather than a knife or gun.

☛ Local Suspects ☚

from the  Mason City Globe Gazette

from the Mason City Globe Gazette

Shortly before his death, Plummer told Emma Jensen that he had gathered enough information on local bootleggers to “make a cleanup” and that after he turned in the names he was leaving Spencer, perhaps within days.

The Spencer News-Herald wrote:

“That Plummer had secured evidence against Spencer bootleggers and expected to report some liquor sales on them within a few days was his statement made shortly before Wednesday, the evening he was beaten. He had been hanging around pool halls and other places watching bootleggers and told some acquaintances that ‘he had the goods’ on some of the liquor vendors and was about ready to ‘turn in the list.’ Reports of Plummer’s statements may have reached some of the bootleggers, police think, which prompted the beating.”

BCI Agents H.C. Yackey and Ray Scott, along with county authorities, brought in and questioned bootleggers and liquor sellers on whom Plummer had evidence.

Investigators were particularly interested in the efforts of local bootleggers to join together to raise the price of liquor and wanted to know if Plummer’s activities were discussed at meetings about this strategy.

Those rounded up denied knowledge of Plummer’s beating and furnished alibis. Some insisted that supplies of liquor in the area were so scarce that there was little selling anyway.

John Kopac, a self-confessed bootlegger who had an outstanding jail sentence and was involved with the liquor ring, was arrested and aggressively questioned but denied any knowledge of the Plummer attack.

☛ “Outside Job”? ☚

Information being uncovered by investigators suggested the killers might not be locals. The Spencer Reporter wrote:

“Sheriff Erickson believes there is a possibility that [Plummer’s] attackers may have been men from out-of-town who had a grudge against the stool-pigeon.”

Spencer News Herald

from the Spencer News-Herald

The victim worked the harvest in South Dakota before arriving in Rockwell City in the autumn of 1928 to pick corn. He persuaded Calhoun County Sheriff John Dellinger to hire him as an undercover agent. When he died, he had papers in his pocket deputizing him there.

Calhoun County Deputy Sheriff A.L. Risley told Clay County investigators that Plummer gathered evidence on 20 bootleggers; 15 of them pleaded guilty, two others were indicted, and three fled to avoid arrest.

According to the Spencer News-Herald:

“[Deputy Risley] hinted that the three who got away and left Calhoun County with their families could have been implicated in Plummer’s beating. One of them had been arrested several times, twice for violations of liquor laws and once for larceny, and Plummer had gotten ‘buys’ on him this time. Another served a year’s term in the penitentiary for driving a car while intoxicated and the third was a well-known gambler.”

Plummer was scheduled to return to testify against those indicted during the next term of district court.

☛ Who Was Clarence Plummer? ☚

The mystery of the victim’s identity was as tangled as that of his murder due to his use of multiple names in multiple locations — papers in his possession indicated he had spent time in Norborne and Chillicothe, Missouri; Omaha, Nebraska; and South Dakota, as well as Keota, Sigourney, Rockwell City, What Cheer, Williamsburg, Lehigh, Anamosa, and Cedar Rapids in Iowa.

According to Spencer law enforcement, he was 5 feet 9 inches tall, bald, had a mole on his right cheek, and had a “very ruddy complexion and a jolly disposition.”

He operated in Spencer and Keota as Bert Cook; Calhoun and Clay counties hired him under the name Clarence Plummer; and Special BCI Agent H.C. Yacky knew him in the past as Bert Pettit. Among his possessions was a checkbook from a Norborne, Missouri, bank bearing the name Louis “Lew” Dayton.

No one knew details about his background or personal history. It was assumed that whatever he said about himself and his family was unreliable because he was always working undercover.

Dayton told Emma Jensen his mother died when he was a child, he was not married, and he had no relatives in the area. He claimed to have been a detective for 20 years all over the United States and once even traveled to Europe to track a bootlegger.

However, he told acquaintances in Rockwell City that he had a mother in What Cheer, Iowa, and a brother in Ohio. He was also thought to have a half-sister in Chillicothe, Missouri, and a son and daughter in Texas.

Photo of "Alice" which Dayton Carried (from the Spencer News-Herald)

Photo of “Alice” which Dayton carried (from the Spencer News-Herald).

Found in his pockets was a photo of a young woman he called Alice who he said lived in Cedar Rapids. The photo was published in the Cedar Rapids Gazette with the hope she might be found and have information on his family.

Letters were also found on his person — written, sealed, and addressed but unsent. One was to Agnes Stark of Omaha. She was contacted and said she knew the victim in the fall of 1928 when he worked as a “stool pigeon.” His address book listed names of known Omaha bootleggers.

Sheriff Fred E. Erickson and Deputy H.A. Wilsey attempted to locate the Chillicothe half-sister through police channels.

The Spencer News-Herald worked hard to track the man’s history, reaching out to other newspapers in towns where the victim had lived and sending along photos and descriptions of him.

The Norborne Democrat responded to the Spencer newspaper’s query:

“Replying to your telegram regarding man believed to have been killed by bootleggers, will say that a man of the description you gave left here last July in a new Whippet car. He gave his name as Louis H. Dayton and was employed on the farm of Dave Herry, R. 1, Norborne, Missouri.

Last June 25th Dayton was held up on the state highway south of here and claims to have been relieved of $3,200 in Liberty Bonds and a diamond ring. Dayton claims that two men and a woman in a car bearing an Iowa license held him up, giving him a severe beating and taking his valuables.

The man drank considerable while here and his story was discounted somewhat. He claimed to have sold a farm in Iowa before coming here and said he came from Cedar Rapids. He had a small account in the Norborne Trust which he closed on July 18, 1928 . . . .

He was pretty much of a ‘four flusher’ while here and anything he said could be liberally discounted.”

Dayton borrowed money without repaying it, forged checks, and bought bootleg liquor before he left Rockwell City. He also swindled a man out of $100 after agreeing to teach him undercover techniques.

Dayton’s past in Norborne, however, was not in keeping with his behavior in Spencer and Rockwell City, where he did not drink or commit other offenses.

Clay County officers and others associated with the victim in Spencer refused to believe Plummer and Dayton were the same man until photographs of Plummer were positively identified by numerous Norborne residents, including a farmer for whom he worked, as well as by the bank where he did business.

☛ Family Members Come Forward ☚

from the  Spencer News Herald

from the Spencer News-Herald

On the day of the funeral, Sheriff Erickson received a call from Iowa City resident Elsie Claypool who said newspaper descriptions of Clarence L. Plummer matched her father Louis H. Dayton, whom she had not seen since November of 1927.

Then other family members also came forward, including his ex-wife Mary E. Dayton — who had obtained an uncontested divorce on the basis of cruelty — son Cloyce K. Dayton of Washington, Iowa, and step-brother Emerson Dayton of Wellman.

The family arrived in Spencer and was acknowledged at the County Attorney’s office as who they claimed to be. In particular, the ex-wife related stories about his early life in Washington, Johnson, and Keokuk counties that matched ones the dead man told in Rockwell City and Spencer. The family also recognized the watch and other items found in his possession.

With many tears, the family members identified Dayton from a post mortem photo and then were taken to the mausoleum. Arrangements were made to bury Dayton with hopes of moving the body at a later date to Iowa City.

☛ Louis H. Dayton ☚

from the  Spencer Reporter

from the Spencer Reporter

Louis H. “Lou” Dayton was born January 15, 1875 near Washington, Iowa. He was married on March 11, 1896 to Mary Ethyl Cowan in Allamakee County. The couple had 9 children: Donald Cowan Dayton, Cloyce K. Dayton, Cecile Claire Dayton Vantol, Lorna Jean Dayton Krebs, James Lewis Dayton, Henry N. Dayton, William Hubert Dayton, Carolyn Dayton Orr, and Elsie Dayton Claypool.

His ex-wife believed that Dayton used fake names to avoid paying alimony. She related that a long-time friend said that even as a young man he took on the names of people he knew, such as Albert Cook and Walter Cook.

He farmed near What Cheer and then worked as a fireman on an engine for the Clay Products Company, a pottery operation. He was an engineer there for three years and had a solid work record.

But Dayton’s true desire was to be a detective.

His ex-wife Mary said he had very little education but liked detective stories; he would read them aloud and sound out unfamiliar words until he could get the meaning.

His daughter Elsie Dayton Claypool told the Spencer News-Herald:

“He always had an inclining to be a detective and believed he had the ability to make a good one. He liked nothing better than to get a problem to work out that required detective work and I’ve always known that he would like to be engaged in work that would give him a chance to do secret investigating.”

In the fall of 1927, he fell ill. Elsie Dayton Claypool left her job and went to Lehigh to take care of him. He then disappeared.

Elsie Claypool said:

“My father could not be called a religious man, but he was a good believer. He was not a regular church goer, but he believed in God and always did his best to live up to the Golden Rule . . . . My father was a great pal to my children, too, and they thought he was the most wonderful man in the world.”

☛ Unsolved Murder ☚

from the  Sioux City Journal

from the Sioux City Journal

Despite the best efforts of law enforcement and perhaps because of his secretive life, the Louis Dayton homicide could not be solved.

On April 16, 1929, the Mason City Globe Gazette — still using one of the victim’s assumed names — wrote:

“Into the category of ‘unsolved murders,’ local officials have about placed the slaying of C.L. Plummer, Special Investigator, three weeks ago. State Agent Hi Yackey has spent much of the time since the slaying here assisting local officers, yet the solution of the mystery seems as remote as it did the night Plummer staggered into his rooming house and mumbled a story of being beaten in front of the Post Office.”

In the Line of Duty

Click here to view “Iowa Department of Public Safety Peace Officer Memorial Page Remembers Deputy Louis H. Dayton.”


Please note: Use of information from this article should credit Nancy Bowers as the author and Iowa Unsolved Murders: Historic Cases as the source.



  • ☛ “Attack Enveloped in Deep Mystery,” Spencer News-Herald, March 28, 1929, p. 9.
  • ☛ “Bootleggers Are Being Quizzed,” Spencer News-Herald, March 28, 1929, p. 1.
  • ☛ “Deputy Sheriff Slain At Spencer,” Burlington Gazette, March 21, 1929, p. 1.
  • ☛ “Evidence at the Coroner’s Inquest,” Spencer News-Herald, March 28, 1929, p. 1.
  • ☛ “Friends of Plummer In Rockwell City Know But Little Concerning Him,” Spencer Reporter, March 27, 1929, p. 9.
  • ☛ “Hold Suspect in Deputy’s Slaying,” Waterloo Evening Courier, March 25, 1929, p. 1.
  • ☛ “Hunt Spencer Rum Dealers for Slaying,” Mason City Globe Gazette, March 22, 1929, p. 1.
  • ☛ “Identify Slain Deputy,” Ruthven Free Press, May 1, 1929, p. 1.
  • ☛ “Identify Slain Deputy’s Body,” Spencer News-Herald, April 25, 1929, p. 13.
  • ☛ “Identity Of Plummer Now Established,” Spencer Reporter, April 24, 1929, pp. 1, 3.
  • ☛ “Iowa City Woman Says C.L. Plummer Was Her Father,” Spencer Reporter, April 17, 1929, p. 16.
  • ☛ “Iowa Slaying Still Mystery,” Sioux City Journal, April 14, 1929, p. 33.
  • ☛ “Look for Slayers Of Deputy Sheriff Among Bootleggers,” Muscatine Journal And News Tribune, March 22, 1929, p. 11.
  • ☛ “Murdered Dry Agent Has Son In Washington,” Davenport Democrat And Leader, April 21, 1929, p. 2.
  • ☛ “Near-by News Notes,” Hawarden Independent, April 25, 1929, p. 6.
  • ☛ “No Relatives Appear To Claim Body Of C.L. Plummer Slain Here,” Spencer Reporter, March 27, 1929, p. 9.
  • ☛ “No Relatives of Dead Man Found,” Spencer News-Herald, March 28, 1929, p. 1, Section 2.
  • ☛ “No Solution Of Mystery Killing Here,” Spencer News-Herald, April 4, 1929, p. 1.
  • ☛ “Police Find No Clues To Murderers Of C.L. Plummer, Liquor Informer,” Spencer Reporter, March 27, 1929, p. 9.
  • ☛ Rolfe Arrow , March 28, 1929, p. 2.
  • ☛ “Special Deputy Sheriff Killed By Unknown Assailants: “Spencer Murder Still Unsolved,” Mason City Globe Gazette, April 16, 1929, p. 22.
  • ☛ “Spencer Official Fatally Slugged by Unknown Men,” Muscatine Journal And News Tribune, March 21, 1929, p. 12.
  • ☛ Spirit Lake Beacon, May 2, 1929, p. 5.
  • ☛ “State Agents Seek Slayers,” Sioux City Journal, March 22, 1929, p. 1.
  • ☛ U.S. Census.
  • ☛ “We’ll Leave It To You,” Spencer News-Herald, April 25, 1929, p. 2.

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