MILLS, Wyo. - A Wyoming police officer has pleaded not guilty to an animal cruelty charge that alleges a police dog died after he left it in a hot patrol car for several hours.

According to an investigator's statement filed in Natrona County Circuit Court, Mills police officer Zachary Miller left the female black lab named Nyx in his patrol car for over six hours July 9.

KCWY News 13 reports the car was running but the air conditioning was off and outside temperatures reached 86 degrees.

The Casper Star-Tribune reports that Miller, a four-year veteran of the Mills Police Department, pleaded not guilty to the misdemeanor charge at a court appearance on Friday.

Nyx had been with the department for almost seven years and lived with Miller's family.