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Key takeaways
- Learn how two veteran detectives cleared five murders across two states without modern forensic tools.
- See why meticulous note-taking, teamwork and communication skills still matter.
- Discover 13 timeless lessons from the detectives who caught a serial killer with grit and respect.
- Understand how rapport and integrity drive confessions — not threats or tricks.
At every agency there are a couple of detectives who earn the reputation of being “the best.” When I still had my new cop smell, those detectives were Joe Dunham and Mike Abraham.
To become the best, they had to work in an era without DNA, security cameras, computers, cell-phone tracking, licence plate readers or real time crime centers. They relied on dusting for prints, intuition, communication, observation, deduction and interview skills to clear cases without high-tech aids.
Now in their 80s, Dunham and Abraham sat down to discuss a case where, using only those basic tools, they stopped a serial killer early in his career — clearing five homicides in two states. Then, they shared the timeless secrets behind their success.
Murder most foul
On March 20, 1987, Detectives Mike Abraham and Joe Dunham were sent to the scene of a burglary and triple homicide on the north side of La Crosse, Wisconsin.
A burglar had entered through a basement window, forced a locked upstairs door and shot three victims — 33-year-old Kenneth Bush, his girlfriend 35-year-old Debra Reget and his mother, 73-year-old Lila Bush — each in separate rooms. Lila had also been beaten. The unknown killer stole $1,500 and fled in the victims’ car.
Working the scene and building leads
Abraham dusted the kitchen linoleum and developed a clear footwear impression. He cut out that section of flooring and preserved it. The .25-caliber slugs from each victim were collected after autopsies. But the most important immediate clue was the burglar’s method: “entering through a basement window.”
A neighborhood canvas led them to the Willow Inn bar, where the owner described a suspicious man using the bathroom to clean up — a man named “Michael Tenneson.”
A criminal history check revealed Tenneson had recently walked away from a La Crosse County Jail work-release program. He also had a prior burglary in nearby Holmen — again, through a basement window.
Evidence builds and the trail widens
Dunham and Abraham contacted Tenneson’s friends, family and roommates. They learned he had recently bought tennis shoes matching the pattern found at the scene and that witnesses had seen him with a Raven .25-caliber semi-automatic pistol.
The victims’ stolen car was found abandoned near Madison. The detectives drove there to process it and canvassed nearby bars. A bartender remembered Tenneson asking, “Where is the closest bus station?”
At that bus station, they confirmed he had boarded a bus to Los Angeles.
A mother’s call from Denver
The detectives contacted Tenneson’s mother — a decent, cooperative woman — and she promised to call if her son reached out. In May, she did. Michael had phoned her from the Denver Jail, where he said he was being held for auto theft.
Dunham and Abraham contacted Denver PD but found no one booked under that name. Eventually, it was learned that a “Michael Leith” in custody was actually Michael Tenneson. Tragically, the Denver Police soon discovered that the owners of the stolen car — roommates Jeffrey Sheffield and Mitchell Gonzales — had been shot to death.
Undeterred, Dunham and Abraham paid their own way to Denver to continue their investigation, hoping to be reimbursed later (they were).
The confession
On May 25, 1987, at 9:47 p.m., Michael Tenneson waived his rights and agreed to speak with Joe and Mike.
There was never a “good cop, bad cop” dynamic with them. Abraham made suspects laugh and relax; Dunham treated them with respect and got down to business. They worked like a finely tuned team, partners since childhood who often finished each other’s sentences.
“You have to first establish a rapport,” they said. “Find some point to bond with the suspect. Buy them a cup of coffee, let them have that cigarette and just relax and bond.”
Once the rapport was built, they discussed the La Crosse homicides. Tenneson admitted he intended only a burglary, picking the house at random. Armed with a Raven .25-caliber, he entered through a basement window and forced the locked upstairs door.
He recalled grabbing a beer when Kenneth Bush confronted him. “A guy came charging out yelling, ‘What the hell are you doing in my house?’ I shot the guy once and he went down.”
Then, he found Lila Bush. “She said, ‘You’re going to Hell.’ I shot the old lady in the back of the head and took $1,500 from her purse.”
Finally, he found Debra Reget hiding in a corner and “shot her two or three times in the head.” Afterward, he cleaned up, left out the front door, stole the car and drove to Madison, then boarded a bus bound for Los Angeles — stopping in Denver.
The Denver connection
Abraham asked, “What did you do with the gun?”
Tenneson answered matter-of-factly, “After I shot the two here (Denver), I threw it in a dumpster by a restaurant,” confessing to two more murders.
He told them, “I deserve everything I get. I wish I could turn it around, but I can’t,” before breaking down in tears — genuine, according to Dunham’s notes.
He offered to show them where he’d dumped the gun, but the search proved fruitless. “We thought it was a ploy to attempt an escape,” they said, “but we never gave him the opportunity.”
Denver investigators later confirmed that Tenneson had befriended Sheffield and Gonzales after helping them during a confrontation. A few days later, he shot them both with the same gun used in La Crosse. He stole their cash, pawned their stereo and fled in their car before being caught in Aurora, Colorado.
Tenneson was convicted by a Denver jury but spared the death penalty by one holdout juror. He later pleaded guilty in Wisconsin, receiving three life sentences — to be served only after his 104 years in Colorado.
13 timeless lessons from legendary detectives
The Tenneson case was just one of the thousands investigated by these two partners that ranged from thefts to homicides. These legendary law dogs were respected by judges, defense attorneys, cops, district attorneys, criminals and the community they served. They were gracious enough to share some wisdom for anyone involved in investigations. Here is a list of advice from these retired pre-technology “gumshoes.”
- Remember “GOYAKOD” — Get off your ass and knock on doors.
- Interview people more than once. They’ll recall things they forgot or withheld.
- Treat everyone — rich or poor — with respect. It pays dividends.
- Establish rapport. Find a way to bond.
- Convince people: “We’re the police, and we’re here to help you.”
- Be good at the basics.
- Be honest. Your word is your currency.
- Document everything. Dunham said, “The only reason I can tell you these details today is because I kept notes.” Abraham added, “You can check my notes on every case — it says ‘See Joe’s notes.’”
- Don’t rely on polygraphs. Learn to read body language. “You can tell a lot by the eyes,” Abraham said.
- Avoid leading questions — some criminals are better interviewers than cops.
- Work as a team. “In Denver, the officers treated us like brothers.”
- Use no threats or promises to get a statement.
- Supervisors: remember the “attaboy.” Recognition matters. Unbelievably these detectives received no formal recognition beyond a thank you letter from Denver’s Captain of Detectives. As Joe put it, “Everyone likes a pat on the back for a tough job done right.”
Would they do it all again?
Clearly, these two enjoyed their careers. When I asked if they’d do it all again, Joe said, “Heavens yes!” and Mike shouted, “Hell yes!”
Maybe I can’t declare them “the best detectives ever,” but I can safely say there were none better.
Training discussion points
- How can rapport-building improve modern investigations?
- Why should today’s investigators focus on basics like note-taking and observation?
- What leadership lessons can modern supervisors take from Dunham and Abraham’s approach?
Tactical takeaway
Ask your senior detectives to share how they built cases before technology. Passing down those old-school skills preserves the craft of real police work.
What’s the most valuable “old-school” investigative skill you’ve learned from a veteran detective?
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