HOUSTON -

There is outrage in Houston after activists learned a police officer will not face charges for shooting and killing an unarmed, double-amputee.

Brian Claunch was shot last September at a group home after police say he threatened an officer with what turned out to be a pen.

Now months after the shooting, new questions are emerging on why the officer who shot Claunch will not be charged.

The Greater Houston Coalition for Justice is speaking out and calling for a change to the grand jury process in Harris County.

"The grand jury process is a secret process and the DA appoints a special prosecutor in these cases," said civil rights lawyer Randall Kallinen.

The group is upset that a Houston police officer will not face charges for shooting and killing an unarmed double-amputee.

An officer shot Brian Claunch in September 2012. Investigators say he was mentally ill and threatened an officer with what later turned out to be a pen, but they say Claunch also cornered the officer with his wheelchair and wouldn't listen to their commands to stop.

The Greater Houston Coalition for Justice thinks charges should have been filed and weren't because of a problem with the way the grand jury operates.

"Oftentimes the officer is not even called in to the grand jury, which has happened before," Kallinen said.