Debra Reget was a 35-year-old White woman whose life ended during a violent home invasion in La Crosse, Wisconsin, on March 20, 1987. She was at the north-side home of her boyfriend, Kenneth Bush, when an intruder entered the residence through a basement window, forced his way through a locked upstairs door, and turned what appeared to have begun as a burglary into a triple homicide. Kenneth, Debra, and Kenneth’s mother, Lila Bush, were each found shot in separate rooms of the house.
Investigators determined that. 25-caliber bullets had been used in the killings. Lila had also been beaten, and approximately $1,500 was stolen before the killer fled in the victims’ automobile.
La Crosse detectives Mike Abraham and Joe Dunham began working the scene with the forensic tools available at the time. One important clue was a footwear impression Abraham developed on the kitchen linoleum. Investigators also focused on the way the killer had entered through a basement window. A neighborhood canvass eventually brought detectives to the Willow Inn, where the owner recalled a suspicious man who had used the bathroom to clean himself up around the time of the killings. That man was identified as Michael Tenneson.
Tenneson quickly became a significant suspect. Investigators learned that he had been serving a felony sentence in the La Crosse County Jail and had failed to return from a work-release outing on March 10, just ten days before Debra and the Bushes were killed. His criminal history also included a previous burglary in nearby Holmen in which entry had reportedly been made through a basement window, a method strikingly similar to the La Crosse crime scene. Detectives subsequently learned from people who knew Tenneson that he had recently purchased tennis shoes consistent with the impression recovered from the Bush residence and had been seen with a Raven. 25-caliber semiautomatic pistol.
The stolen vehicle was eventually located abandoned near Madison. Abraham and Dunham traveled there to process the car and continued tracing Tenneson’s movements. A bartender remembered Tenneson asking where he could find the nearest bus station, and investigators determined that he had boarded a bus headed west. Although the initial trail pointed toward Los Angeles, Tenneson ultimately remained in Denver, Colorado, where he used the name Michael Leith.
For approximately two months, Tenneson remained outside Wisconsin. The investigation broke open after his mother notified La Crosse detectives that her son had contacted her from the Denver area and said he was in jail. Police eventually discovered that a prisoner being held under the name Michael Leith was actually Tenneson. By then, Denver authorities were investigating another double homicide. Jeffrey Sheffield and Mitchell Gonzales had been shot to death, and Tenneson came under suspicion after being connected to Sheffield’s automobile. He was arrested in Colorado on May 21, 1987.
Abraham and Dunham traveled to Denver and interviewed Tenneson on May 25. After waiving his rights, Tenneson confessed to the La Crosse killings. According to the detectives’ later account, he said he had selected the Bush residence at random and initially intended only to burglarize it. Armed with the. 25-caliber pistol, he entered through the basement and forced his way upstairs. Kenneth Bush confronted him, and Tenneson admitted shooting him. He then encountered Lila Bush and shot her before taking money from her purse.
Tenneson told investigators that he eventually found Debra hiding in a corner. He admitted shooting her multiple times in the head. After the three victims were dead, he said he cleaned himself up, walked out the front door, took the vehicle from the residence, and drove toward Madison before continuing his flight by bus. Investigators later determined that the gun associated with the Wisconsin killings was also used in the two Denver murders. Tenneson told detectives that he disposed of the weapon in a dumpster after the Colorado shootings, although investigators were unable to recover it.
The prosecution of Tenneson unfolded first in Colorado. On March 18, 1988, a Denver jury convicted him of two murders in the deaths of Sheffield and Gonzales, along with aggravated robbery and aggravated automobile theft. Prosecutors sought the death penalty. During the penalty proceedings, information about his confession to the Wisconsin murders became part of the case. The Colorado jury ultimately failed to reach the unanimity required to impose death, with eleven jurors reportedly favoring execution and one refusing to do so. Tenneson received two life sentences for the Colorado murders, together with additional prison terms for robbery and automobile theft.
Tenneson was then returned to Wisconsin to answer for the killings of Debra Reget, Kenneth Bush, and Lila Bush. On June 14, 1988, rather than proceed through a full murder trial, he pleaded guilty to three counts of murder. As part of the disposition, additional allegations, including armed burglary, possession of a firearm by a convicted felon, and a repeat-offender allegation, were dismissed. He was sentenced to three life terms in Wisconsin, to follow the lengthy sentence already imposed in Colorado.
The investigation therefore did not leave Debra Reget’s killing unresolved. Michael Tenneson was identified through the combined work of the La Crosse detectives, physical and circumstantial evidence linking him to the scene, the trail created by the stolen vehicle and his flight from Wisconsin, and ultimately his own confession. His admission provided investigators with a detailed account of how the burglary escalated into the killings of three people inside the La Crosse home. His guilty plea and three Wisconsin life sentences formally established his responsibility for Debra’s death and the deaths of Kenneth and Lila Bush.
