Authorities in western Ohio say a police dog has died after being left in a hot patrol car by his handler. Mercer County Sheriff Jeff Grey says a deputy left his K-9 unit named Zak in his patrol car at the sheriff's office in Celina while he completed the reconstruction of a traffic crash Wednesday afternoon. The Dayton Daily News reports Grey says the car should have been left running with the air conditioning on when at the office or the dog should have been brought inside. Grey says the car was not running. Authorities say the dog had a pre-existing heart condition and is believed to have died after being aggravated by the car's heat. The sheriff's office is investigating and suspending the K-9 program until further notice.