Crime Library: Criminal Minds and Methods

Joseph Edward Duncan III

"Concrete Bob"

Robert Roy Lutner
Robert Roy Lutner

According to information released by the Kootenai County Sheriff's Department on Wednesday, May 18, a "person of interest" surfaced in the case following interviews with relatives and friends of the victims. Robert Roy Lutner, 33, also known as "Concrete Bob," a moniker he had been given because of his work in the concrete and construction industry, was a friend of the victims and had visited them twice in recent days — once on the Friday afternoon preceding the murders and again on Sunday evening, which was believed to have been the day of the slayings. A relative of the Groene's told detectives that Lutner owed Brenda Groene and Mark McKenzie $2,000. However, the relative told the investigators that no one in the family had indicated that there might have been any trouble between them and Lutner, and there was no indication that he was being pressured to repay the money even though the family needed it.

Mark McKenzie, victim
Mark McKenzie, victim

"I never saw him hostile toward my family at all," the relative said, according to a news report in the Spokesman-Review.

Further investigation revealed that Lutner had been in trouble before, and in fact his criminal record in the county was somewhat lengthy.  He had been in trouble on drug possession charges in 1992, and had been arrested for domestic battery in 2004 in an incident outside a bar that involved a fight with a girlfriend. That charge had been eventually reduced to disturbing the peace. He was convicted twice for fraud for improperly representing unemployment claims and was currently on probation for those convictions.

Lutner, at six-foot, three-inches and weighing in at 230 pounds, was someone the cops definitely wanted to talk with. However, they first had to find him.

Searchers cover a trail
Searchers cover a trail

He was seen at a bar in the area on Sunday afternoon, which would have been prior to being seen at Groene and McKenzie's home. Two days later, on Tuesday, he talked to his probation officer on the telephone and said that he was making a trip to Boise. By that time, he had heard about the murders and was crying while talking to a family friend of the victims, but the authorities were not yet looking for him as a person of interest in the case. That all changed, however, in a matter of hours after investigators pieced together the sequence of events that had placed Lutner at the Groene-McKenzie residence prior to the murders.

The next day, Wednesday, May 18, Lutner learned that the investigators were looking for him and he turned himself in to sheriff's deputies in Coeur d'Alene. He was interviewed over the next several hours and denied having anything to do with the murders. He took a polygraph and passed it with flying colors, and was subsequently dropped as a person of interest in the case, leaving investigators back at square one.


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