HOUSTON -

Houston police said an officer opened fire on a man in a wheelchair who had only one arm and one leg.

According to detectives, the officer responded to a domestic disturbance complaint at a group home on Polk and Sidney in southwest Houston around 1:30 a.m. Saturday.

Police said the person in charge of the home said the man inside, Brian Claunch, had a history of mental illness and was threatening other residents.

"When officers arrived and went inside to speak to him, he was situated in a wheelchair holding an unknown object," said Jodi Silva with the Houston Police Department.

The officers said Claunch was swinging the object in a threatening manner towards them and the residents. Investigators said the officers told Claunch to drop the object, but he refused. That's when police said five-year veteran Matthew Marin fired his gun at Claunch, shooting him in the head.

Officials with the Houston Police Department said the object Claunch was wielding turned out to be a pen.

"It's tight quarters in there, and he was able to corner the officer back into the corner of the room," said Silva.

Claunch was pronounced dead at the scene.

Homicide detectives as well as Internal Affairs are investigating the case. Marin will work three days of desk duty. The Houston Chronicle reports that Marin shot someone else in the line of duty three years ago.

The head of a local police violence group questions whether Marin was justified in shooting Claunch. Civilians Down co-founder Arlene Kelly told the newspaper that she wonders how dangerous a suspect is if he only has one arm and one good leg.