Investigators said they didn't find anything out of the ordinary inside the home.

Tulsa police say Sudheer Khamitkar shot and killed his wife Smita and two sons Arnav and Arush in their east Tulsa home.

Police say Sudheer then turned the gun on himself.

“It's just one of those things you never expect to happen," neighbor Tom Spehar said.

Spehar says he's saddened it happened to such a loving family.

“They were just very nice people,” Spehar said. “There's no reason, no rhyme or reason why this should happen to that type of family -- two very nice kids, very young kids, it's hard."

Broken Arrow Public Schools say the sons attended Country Lane Primary and Intermediate Schools.

School officials are working with classmates and teachers and offering counseling as they deal with the tragedy.

"It's been a very difficult day at the site, but things are going well,” BA Public Schools Jarod Mendenhall said. “I mean, they're kind of trying to do the things that they've done on a typical Thursday in April, so they've kept things as normal as possible."

Officers discovered the family dead after one of Smita's coworkers told police she had missed two days of work.

Sgt. Dave Walker says his investigators didn't find a suicide note or any indications that anything was wrong inside the home.

He said investigators may conduct more interviews with family and coworkers, but they have closed the case.

"I don't know if we'll ever know why, and that will be the continuing haunting question that we get as investigators,” Walker said. “Everybody wants to know why, even us."

"He was a very intelligent man, I know he was,” Spehar said. “I've talked to him on several occasions with his family out there, it's just difficult.”