"They argued a little bit, but nothing significant," Judd said.

It wasn't the first argument for the couple who'd been married for 10 years. According to an arrest affidavit, Troy Bellar accused his wife of hitting, punching and scratching him in March. Wendy Bellar was arrested on suspicion of domestic battery, and the case was pending.

Sunday night's gunfire sent panicked neighbors to their phones to dial 911. One of them told an emergency dispatcher she saw the teen "running around in the garage with his hands up, and like screaming," according to a recording of the call.

After Nathan safely reached the home of another neighbor, that woman relayed information from him to a 911 dispatcher.

"A boy's here at my house that lives there and says that his dad shot his mom and there's a baby there," the neighbor, who was not identified, told a 911 operator.

"I know this is going to be very hard for you to ask him," the operator said. "Is his mom still alive?"

After an exchange between the neighbor and the boy, the woman told the operator: "She got shot in the head."

Wife, sons were found on porch
Deputies arrived at a horrific scene: Wendy Bellar and her two young sons dead from gunshot wounds in their screened-in porch and their father lifeless in the front yard. A preliminary investigation indicates that more than 10 rounds were fired in all.

"It left veteran detectives and crime scene technicians that do this for a living stunned last night," Judd said.

Detectives praised the surviving teen for being helpful.

"He cried some, as you can imagine," Judd said. "As he should have done. And he was very quiet. And we were very delicate with him."

Investigators say Troy Bellar ran a home remodeling and handyman business, which next-door neighbor Doug Lane said seemed to do a steady business despite the economic downturn.

"He said the remodeling had dropped off, but he was doing repair work for commercial apartments and that sort of thing," Lane said. "He said that he was staying busy."

Judd couldn't say if the family was experiencing any financial difficulties.