Lila Bush, a 73-year-old White/Caucasian woman, was killed inside her home on the north side of La Crosse, Wisconsin, on March 20, 1987. What initially confronted investigators was a horrific triple homicide. Lila was found dead along with her son, Kenneth Bush, and Kenneth’s girlfriend, Debra Reget. All three had been attacked in different rooms of the residence, and investigators determined that the killer had entered the house through a basement window before forcing his way through a
locked door leading to the upper portion of the home. Lila had been beaten as well as shot.
The man eventually identified as the killer was Michael Tenneson, who was already a fugitive when he entered the Bush residence. Tenneson had been serving a felony sentence through the La Crosse County Jail and had been participating in a work-release program when he failed to return on March 10, 1987, ten days before the murders. Investigators later learned that his method of entering the Bush home through a basement window resembled a burglary he had previously committed in nearby Holmen, providing detectives with an important connection between the crime scene and Tenneson.
According to Tenneson’s later confession, he did not know the Bush family and had selected the residence as a burglary target. He was carrying a Raven. 25-caliber handgun when he climbed through the basement window and forced open the locked interior door. Once upstairs, he took a beer from the home. Kenneth discovered the intruder and confronted him, and Tenneson shot Kenneth. Rather than fleeing after the first shooting, Tenneson continued through the residence looking for other occupants and valuables.
Tenneson then encountered Lila. According to the account he later gave detectives, she confronted him verbally, telling him that he was going to hell. Tenneson responded by shooting her in the back of the head. Investigators determined that approximately $1,500 was taken from her purse. He subsequently located Debra Reget hiding in another part of the house and shot her multiple times in the head. The use of the same. 25-caliber weapon against the three victims became an important part of reconstructing the killings.
After killing all three people, Tenneson attempted to clean himself up and left the residence through the front door. He stole the victims’ automobile and drove away from La Crosse, eventually abandoning his immediate ties to Wisconsin and traveling west. The investigation quickly began producing clues. A neighborhood canvass led detectives to the Willow Inn, where the owner remembered a suspicious man who had used the restroom to clean himself up around the time of the murders. That man was identified as Michael Tenneson. A records check then revealed that Tenneson was the work-release fugitive whose previous burglary also involved entering through a basement window.
Tenneson made his way to Denver, Colorado, where his violence continued. On May 20, 1987, roughly two months after the La Crosse murders, he killed Jeffrey Sheffield and Mitchell Gonzales. Both men were shot in the head after an evening involving alcohol and drugs. Tenneson then took property belonging to the victims and used Sheffield’s automobile. His behavior with the stolen vehicle helped draw the attention of Colorado authorities, and he was taken into custody on murder charges on May 21.
La Crosse detectives Mike Abraham and Joe Dunham traveled to Colorado to question Tenneson. On May 25, 1987, Tenneson waived his rights and agreed to speak with them. During the interview he confessed to the Bush-Reget murders, describing how he entered the house, encountered each victim and killed them while committing the burglary. He also admitted that the same gun had been used in the two Colorado killings. Tenneson told investigators where he claimed to have discarded the weapon, although a search failed to recover it.
Colorado prosecuted Tenneson first. In March 1988, a Denver jury convicted him of two counts of first-degree murder for the deaths of Sheffield and Gonzales, as well as aggravated robbery and aggravated automobile theft. Prosecutors sought the death penalty, and eleven jurors reportedly favored execution, but Colorado law required a unanimous jury for a death sentence. One juror would not vote for execution, resulting in life imprisonment instead. Tenneson received two life sentences for the Colorado murders, along with additional sentences totaling 48 years for the robbery and automobile-theft convictions. Contemporary accounts calculated that he would have to serve approximately 104 years before becoming eligible for parole under those sentences.
After the Colorado prosecution, Tenneson was returned to Wisconsin to answer for the deaths of Lila Bush, Kenneth Bush and Debra Reget. On June 14, 1988, rather than proceeding through a full Wisconsin murder trial, he entered guilty pleas to three murder counts. As part of the resolution of the case, other allegations, including armed burglary, possession of a firearm by a convicted felon and a repeat-offender enhancement, were dismissed. Tenneson received three additional life sentences for the La Crosse killings, to follow the lengthy sentences imposed in Colorado. The investigation that began with an unknown burglar inside the Bush home had ultimately established that Lila and the other two victims were killed by a fugitive who went on to commit two more murders before his arrest and confession.
