PAYSON, Utah - Mystery surrounds a homicide investigation in Payson. Investigators have been tight-lipped while friends and neighbors wonder who would kill retired BYU professor, Kay Sherman Mortensen. Long-time friend Carl Marvin says, "he was a gun collector and he had a lot of nice guns." Kay Mortensen's arsenal was well known in Payson. Friends say he studied karate, was physically strong and can't believe he was overpowered. Neighbors say Mortensen was killed Monday night in a home invasion while his son and daughter in-law were bound with zip ties.

Many describe Mortensen as a wonderful friend and respected engineer with a brilliant mind.

"He could do anything," says neighbor Carl Mavin. "I needed to put in a water line from the canal. He just came and dug it for me that's the kind of friend he was he'd do anything for anybody. And I'm beside myself someone would come and do such a thing to this man."

But a source close to the investigation says Mortensen was often in legal battles. He had recently testified in a trial and made enemies.

"I didnt see that, he's always been a good friend to me," says Mavin. "Now he was plain spoken, you knew how you stood with him."

No one has been arrested and deputies aren't revealing any suspect descriptions to the media.

Detectives say the homicide was an isolated incident. The Utah County Sheriff's Office says it is dedicating all resources to finding out what happened to Mortensen.

FOX 13's Arikka Von reports.

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