LAKE CUSHMAN, Wash. -- A 56-year-old woman is dead and her husband of 37 years is custody after investigators say a Thursday afternoon argument turned deadly.

The shooting happened just before 4 p.m. in the 100 block of N. Fairway Drive East in Lake Cushman.

Deputies originally thought the shooting might have been an assisted suicide, but they now believe the 64-year-old man killed his wife following an argument, according Chief Dean Byrd with the Mason County Sheriff's Office.

"Initially, there was some indication that this might have been a mercy killing, but that does not appear to be the case now," he said.

Byrd said there is no indication that the victim was terminally ill, but he said investigators won't know for sure until an autopsy is performed.

It's unclear exactly what led up to the shooting, though Byrd said alcohol might have played a role.

"We don't know what the argument was about, but certainly it escalated to a horrible result," he said.

Sam Hutson lives just three houses away from were the shooting took place, but he said he didn't know the couple because they only recently moved in. Though they were new to the neighborhood, Hutson said it's shocking to hear that such violence can happen in such an idyllic community.

"It's insane," he said. "There's a lot of kids up here, a lot of elderly (people,) and everyone pretty much knows everybody."