Officials in Iowa are investigating the cause of death of a police dog that was left in a patrol car on a hot Wednesday afternoon.

The Labrador retriever, named Harley, was a 7-year veteran of the Des Moines Police Department, NBC station WHO reported.

Officials were unsure whether the car's air conditioning was on, if any windows were rolled down or how long the yellow lab was in the car, The Des Moines Register reported.

The incident occurred Wednesday afternoon, according to CBS station KCCI. Des Moines' recorded high temperature Wednesday was 95 degrees, according to The Weather Channel.

Police say Harley was paired with Officer Brian Mathis on the department's vice and narcotics unit.

"What we know is that when he came back to the car, his partner of seven years had died," Des Moines Police Sgt. Chris Scott told the Register.

Officials said Mathis had no history of handling the dog poorly, according to the Register, and Des Moines police have eight other K-9s.

"[Harley's] investigations have taken a lot of drugs off the streets," Scott told CBS station KCCI. "Harley was not a stranger to anybody down here. We lost a fellow officer who just happened to be a dog."

Scott said officials were determining whether criminal charges would be filed, WHO reported.

“There is nobody that could be more upset and traumatized by this than Officer Mathis,” Scott told WHO.

The Police Department's public information office did not immediately respond to a voice mail Friday afternoon.

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