A police dog died Monday in Houston after being left in a patrol car without air conditioning, the second heat death of a police dog around the United States this month.

The dog, a 4-year-old named Aron, had been working with the Houston Police Department for a year and a half. The department released a statement on Twitter Tuesday announcing that Aron died from heat exhaustion.

Aron's handler left him in the car when it was running and had air conditioning on, "which is a necessary and common practice when the K-9 partner is not actively engaged in police work," according to the statement. However, upon returning to the patrol car, Aron's handler found the dog in distress inside the car, which was off. The dog was then taken to an emergency vet where he died from the heat.

HPD Statement regarding the death of K9 Aron#hounews pic.twitter.com/qx8CU2ny4L

The patrol cars designed for K-9 units include built-in features if the car turns off, such as notification of the dog's handler, sounding of the horn, activation of cooling fans, and rolling down the car windows. According to the police department, these features did not work properly when the car turned off with Aron inside it.

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Following Aron's death, the Houston Police Department began investigating the situation to learn how the car turned off and how to prevent it from happening again in other patrol cars. The statement said the police department is having the car vendor inspect all patrol cars handing K-9 units to double check that the notification feature is working correctly.

The incident marks the second time this month that a police dog has died after being left in a hot patrol car. A police dog named Chase who worked for the Cobb County Police Department in Georgia died on June 5 after the car unexpectedly turned off with him inside.

Chase was left in a patrol vehicle while officers attended an active shooter training at a local high school. Officers had been checking on the dog every hour, but at some point, the car's air conditioning system failed. A press release from the police department stated that other safety systems designed to keep the vehicle cool did not work.

"This is a horrible incident and our investigators are continuing to gather information regarding the vehicle system failures that led to this tragedy," the statement said.