HOUSTON -- An 11-year-old boy found his parents dead in their Montgomery County home, the victims of a murder-suicide after a violent argument, officials told KPRC Local 2 Thursday.

Investigators said the couple's bodies were discovered in their house in the 28000 block of Stone Fox Drive at about 7:30 p.m. Wednesday.

The boy found the mother, Sharon Robbins, in the living room and emergency crews later found the father, Richard Robbins, dead in an upstairs bathroom.

Detectives said Richard Robbins killed his estranged wife with a high-powered rifle.

"Everything at this point is leaning toward that he did shoot her. She also had some injuries to her neck that appeared to have been done with a box-cutter that we found in area," said Sgt. Melvin Franklin with the Montgomery County Sheriff's Office.

Franklin said the couple was going through a divorce and Sharon Robbins was no longer living in the home. She was staying with her mother, who lived nearby.

Sharon Robbins went to talk to her estranged husband Wednesday.

Her mother became concerned when she did not return home.

She told her grandson to go into the home because he was the only one who knew the security code to enter it.

"That was the time he ran outside, distraught obviously. Neighbors heard this and called 911," Franklin said.

Neighbors were shocked. They said there was never any trouble at the home and typically no trouble in the neighborhood.

Neighbor Larry Matthews is worried for the boy.

"The little boy was real nice, sociable and friendly, was always out playing -- real polite. Nothing like this ever happens out here," he said.

Investigators said Sharon and Richard Robbins had gunshot wounds to the head.

The boy is staying with his grandmother.