In his 1996 book Mind Hunter: Inside the FBI's Elite Serial Crime Unit, John Douglas describes his initial profile of Alaska's suspected serial murderer. According to Douglas, the perpetrator specifically chose prostitutes and topless dancers, because the majority were transients and usually went unnoticed. Upon the urging of local investigators, Douglas began looking into Robert Hansen's background. He took note of the fact that Hansen was of small stature, heavily pockmarked and suffered from a severe speech impediment. Due to Hansen's unsightly looks, Douglas surmised that he suffered from severe skin problems as an adolescent and was probably teased by his peers. In turn, he would have low self-esteem, which would have prompted him to live in an isolated area. Douglas considered the abuse of prostitutes a way for perpetrators to get back at women. If Hansen was the killer, he was probably using them as a way to get his revenge. Several investigators were familiar with Hansen and said that he was known around the area as a proficient hunter. He earned this reputation after taking down a wild Dall sheep with a crossbow. Perhaps, Douglas surmised, Robert Hansen tired of elk, bear and Dall sheep, and had instead turned his attention to more interesting prey. As the profile progressed, Douglas told investigators that if Hansen was the killer, he was probably a "saver" and would be keeping small souvenirs from his victims.
The only way to rule Hansen out as a suspect would be for investigators to find a hole in his alibi. Douglas suspected that his friends were lying for him and encouraged investigators to threaten them with charges if they were found to be lying. State Police sergeant Glenn Flothe decided to bring the men in for questioning. As it turned out, the strategy worked and both men confessed and said that they had not been with Robert Hansen on the night the young prostitute was abducted and brought to the airport. Investigators also learned from Hansen's friends that he was committing insurance fraud. Apparently, a burglary he reported to police in which several items were stolen from his home never occurred and Hansen was hiding the items in his basement. After learning of Hansen's deceit, Flothe went before Judge Victor Carlson with a 48-page affidavit and secured eight search warrants to be executed against Robert Hanson and his property.
On October 27, 1983, investigators followed Hansen to work and asked him to come with them to the police station for questioning. Hansen never bothered to ask why they wanted to talk to him and agreed to go along. Simultaneously, two groups of investigators served warrants on Hansen's house and plane. According to the book Hunting Humans by Michael Newton, investigators found weapons throughout the house, but nothing to implicate Hansen in any of the murders. Then, just as they were about to call it a day, one of the officers discovered a hidden space tucked away in the attic rafters. Within it, they discovered a Remington 552 rifle; a Thompson contender 7-mm single-shot pistol; an aviation map, with specific locations marked off; various pieces of jewelry; newspaper clippings; a Winchester 12-gauge shotgun; a driver's license, and various ID cards, some of which belonged to the dead women. As incriminating as these items were, the most important piece of evidence was found last -- a .223-caliber Mini-14 rifle.