WASHINGTON -- An Ohio grand jury on Monday decided not to indict Timothy Loehmann and Frank Garmback, the Cleveland police officers involved in the fatal 2014 shooting of Tamir Rice, an unarmed 12-year-old boy. Tamir joins the list of Americans shot to death by police officers who were never held accountable. This year, that list got much longer.

Police in the United States killed more than 1,100 people in 2015, the vast majority by firearm, according to The Guardian . Most of these cases didn't achieve notoriety. But in at least 14 fatal shooting incidents that received substantial press attention, prosecutors and grand juries declined to hold the officers responsible. In most of these cases, the victims were unarmed.

The number of cops indicted for murder actually jumped in 2015, with at least 14 officers charged for on-duty killings over a five-month period, The Atlantic reported in August. One of those officers was Michael Slager, a former South Carolina cop who shot and killed Walter Scott , an unarmed black man, as he ran away.

Prosecutors are typically reluctant to bring charges against police officers. But as bystander videos of shooting incidents grow increasingly common -- and as many of these videos dramatically contradict police narratives -- officials have come under more pressure to hold law enforcement officers accountable. Still, it remains rare for officers to face charges over shooting deaths. Here are 14 notable instances in 2015 when cops walked after killing someone.

Tamir Rice

Last year, Loehmann, a rookie on the Cleveland police force , shot Tamir, a 12-year-old boy playing with a toy gun in a park. This week, a grand jury declined to indict Loehmann and Garmback, the other officer who responded to the scene. "It would be irresponsible and unreasonable if law required a police officer to wait and see if the gun was real, said Cuyahoga County Prosecutor Timothy McGinty.