Houston, Sep 25 (IANS): The Federal Bureau of Investigation (FBI) has been asked to help investigate a police officer's fatal shooting of a wheelchair-bound double amputee, a media report said.

Houston Police chief Charles McClelland asked the FBI to help with the investigation, reported Xinhua citing TV channel ABC13.

Houston police officer Matthew Marin shot and killed one-armed and one-legged Brian Claunch Saturday inside a group home for the mentally ill when responding to a call that Claunch was causing a disturbance inside the home. Claunch died of a gunshot wound to the head.

Police said Claunch threatened Marin and was waving an object at the time of the shooting. Marin reportedly told investigators he didn't know the object in Claunch's hand was a writing pen.

The shooting death of a mentally-ill wheelchair-bound man by a police officer raised public concerns about how the police deal with the mentally ill.