( CNN ) -- The chief of Houston 's police department has asked the FBI to help investigate why an officer shot and killed a disabled man Saturday . Over the weekend , police said that the wheelchair-bound man was acting aggressively and had tried to stab an officer with a pen . `` The Houston Police Department places the highest value on human life and events like these are tragic and unfortunate for everyone involved , '' Chief Charles A. McClelland said in a press release Monday afternoon . `` All Houston Police Officers receive mandatory crisis intervention training specifically dealing with persons experiencing mental crisis . As we do in all instances of this nature , the Houston Police Department 's Homicide and Internal Affairs Divisions , and the Harris County District Attorneys Office , Civil Rights Division , are investigating this incident . '' Police kill amputee in wheelchair at group home for the mentally ill. McClelland vowed to be `` open and transparent in all aspects of our response to this tragic event . '' `` It is my desire to have everyone reserve judgment until all the facts and evidence in this investigation have been gathered , '' his statement read . On Saturday officers went to a group home for the mentally ill where Brian Claunch lived . A reported schizophrenic , Claunch was acting aggressively because his caretaker refused to give him a cigarette and a soda , according to police and the facility owner . Police said Claunch was clutching an object as he advanced on one of the police officers . `` The officers made verbal commands for the suspect to drop whatever he had in his hand , to stay still and to speak with the officers , but the suspect continued to make threats , '' Jodi Silva , a police spokeswoman , told CNN affiliate KTRK in Houston . Claunch trapped one officer with his wheelchair in the corner of a room `` where he could n't get out , '' said a Houston police department representative who declined to be identified . As he advanced toward the officers , Claunch was `` refusing to show his hands , '' the representative said . The object turned out to be a pen , which Claunch attempted to stab the cornered officer with , according to police accounts reported in the media , including by KTRK . The other officer , Matt Marin , was `` in fear of the safety of his partner and the safety of himself , '' Silva said . Marin shot Claunch in the head , police said . On Sunday , the unidentified police representative offered more details , saying that , unlike his partner , Marin was not cornered at the time he opened fire . Claunch died at the scene , investigators . said . Marin has been placed on administrative leave per department policy , police said . The incident was the second shooting involving Marin . In October 2009 , he shot and killed a knife-wielding man who stabbed his girlfriend and a neighbor , according to published reports at the time . Marin joined the Houston Police Department in 2007 . Claunch had been at the Healing Hands group home for 18 months , owner John Garcia told KTRK . He lost an arm and a leg in a train accident . Houston police have not released the identity of the man , though Garcia identified him as Claunch . Garcia told the Houston Chronicle that Claunch liked to `` doodle , '' which may explain why he was holding a pen . Garcia reportedly said he had given Claunch a black felt pen for drawing . Garcia told the Chronicle he did not know if that was the pen Claunch was clutching when he was shot . Garcia said Claunch suffered from schizophrenia and a bipolar disorder . `` He had a temper . He could fly off once in awhile , '' he told CNN affiliate KHOU . Claunch was capable of flying into outrage and making people in the house feel threatened , even though he was confined to a wheelchair , Garcia said . `` Emotionally disturbed individuals , when threatened , are going to react , in most instances , excessively , '' Dr. Ed Reitman , a clinical psychologist , told KTRK . `` This was an incident that did n't have to take place if the individual -- a police officer -- had been trained in dealing with emotionally disturbed individuals . '' CNN 's Nick Valencia contributed to this report .
On Saturday , Houston police officer shot disabled man in head , killing him . Houston police chief : " We are not going to tolerate this type of behavior from our officers and we will hold them accountable for their actions" Comment: Police representative said man had tried to stab officer with a pen .