A Mills Police officer is accused of the negligent death of a K9.

Officer Zach Miller has pleaded not guilty to one misdemeanor charge of cruelty to animals.

Investigators with the Wyoming Department of Criminal Investigation say in July, K9 Nyx, who was assigned to Miller, was left behind in excess of six hours, in a patrol vehicle outside of the Mills Police Station.

During that time, the temperature had gone from 53 to as hot as 86 degrees, and Nyx died as a result.

It was not discovered until Miller and a co-worker were about to respond to a call, when they found Nyx was dead.

It was later determined that Nyx had been left in the police vehicle with the engine still running, the doors locked, the windows were up, and the air conditioner was not on.

When interviewed, Miller said he first yelled at his co-worker for not leaving the air conditioning on, and then later acknowledged that Nyx was his responsibility.

Miller is awaiting trial and could face up to 6 months in jail and/or a $750 fine if convicted.