OAKLAND -- A police officer fired for throwing a tear gas grenade into a crowd of Occupy Oakland protesters who were tending to a wounded comrade is getting his job back.

An arbitrator on Wednesday overturned the Police Department's termination of Officer Robert Roche and ordered him reinstated with back pay.

Roche became the lightning rod over police handling of the 2011 Occupy protests when he was caught on camera tossing the grenade into a crowd of protesters trying to assist Iraq War veteran Scott Olsen.

The grenade incident came less than a minute after a police officer who has never been identified struck Olsen in the head with a lead-filled beanbag, fracturing Olsen's skull and causing him permanent brain damage. Olsen received a $4.5 million settlement from the city earlier this year.

Rachel Lederman, who represented Olsen, said she was stunned by the arbitrator's ruling.

"It really gives you pause that he would be reinstated when you have such a blatant case of police misconduct that is caught on video and publicized all over the world," she said. "It points out that there is still an endemic problem in OPD when it comes to trying to impose any kind of discipline even in a case like this where the evidence is so clear."