The retired Brigham Young University professor who died Monday in a home invasion collected high-powered firearms, some of which may have been automatic, a neighbor said.

The neighbor also said the bandits who killed Kay Sherman Mortensen, 70, also tied up the man's son and daughter-in-law as the family was preparing to play board games.

"Kay was fairly well armed," Kent Carroll said. "I think he figured the country was kind of going to hell in a hand basket and he was preparing for it."

Police scanners on Tuesday in Salt Lake City broadcast an alert warning officers to watch for suspects from Utah County. The description matched that of the suspects in the Payson home invasion and told officers the suspects may be armed with high powered rifles. No arrests have been made.

Mortensen died Monday night during what the Utah County Sheriff's Office said was a home invasion robbery at Mortensen's hillside home southeast of Payson. The office has disclosed few other details and declined to confirm a police dispatcher's early report that someone's throat had been cut.

Deputies are seeking two men in T-shirts and jeans. At least one of the men was described as having short hair dyed black. Witnesses also reported one of the men had a goatee. Investigators are looking for a blue 1991 Ford Escort station wagon.

Carroll said he does not know who would have wanted to hurt the Mortensen family and did not hear or see anything Monday. Carroll's home is about a quarter mile from Mortensen's, and he helped watch Mortensen's home while he and his wife were serving an LDS mission. The mission, in Cove Fort, ended last month.

Monday is considered family night in many Mormon households. Carroll said Mortensen's son and daughter-in-law were visiting so they could play board games. Mortensen's wife was in the Salt Lake Valley helping a daughter who just gave birth, Carroll said.

In addition to killing Mortensen, a retired mechanical engineering professor at BYU, the robbers tied up the son and daughter-in-law, Carroll said.

"I think what happened is Kay let his guard down when somebody knocked or rang the doorbell," Carroll said.

Carroll said he talked to Mortensen's wife after the attack and she told him some of what had happened.

Carroll said Mortensen collected firearms, some of which required special permits and may have been fully-automatic. The federal government requires permits for automatic or certain high-powered weapons, but it could not be verified Wednesday night what kind of permits Mortensen possessed.

"I'll miss the guy," Carroll said. "I enjoyed the guy even though somebody must not have liked him."

ncarlisle@sltrib.com