Sgt. Jason Woodruff said in a statement that Mason’s handler, Corporal Josh Coleman, forgot the dog was still in the back seat of his patrol car. He found Mason unresponsive and rushed him to a veterinarian, but Mason died the next day.

Woodruff said Mason’s death was an accident and no criminal charges would be filed.

>>UPDATE: Authorities now say the case will go to a grand jury, and charges are possible. Read more here.

The department had just celebrated Mason’s birthday 10 days earlier.