Houston police are investigating the death of a four-year-old K-9 who suffered heat exhaustion after being left in a patrol car as temperatures rose into the 90s on Monday, police said.

A handler left Aron, the K-9, in a car with the air conditioner on while the vehicle was running, the Houston Police Department said in a news release.

"When Aron's police handler returned to the vehicle, it was discovered that the engine had shut off and Aron was in distress," police added.

The K-9 was taken to a clinic but ultimately succumbed to the heat, the release stated.

"We lost a member of our K-9 family in a tragic accident," police said, adding that Aron had served with the department for about a year and a half.

Houston Police Department K-9 vehicles are equipped with a system that notifies the handler, activates cooling fans and rolls down the windows should a vehicle shut down, police said. However, "this did not happen in this instance," the release said.

Now the department is investigating to determine what "went wrong" and to prevent incidents like Aron's death in the future, according to the release.

"All HPD vehicles that transport K-9s will immediately be inspected by the vendor to ensure the systems are working properly," the release read.

The National Weather Service in Houston has been warning residents of heat index values this week that can reach as high as 108 degrees Fahrenheit. On Monday, the city experienced a high temperature of 95 degrees Fahrenheit, according to CNN Weather.

When temperatures are 90 degrees, the interior of a car can soar as high as 109 degrees in just 10 minutes, some experts say. Dogs don't sweat and must cool off primarily through panting, according to animal rights advocacy group PETA, and can die from a heatstroke quickly even if the car is parked in shade with slightly open windows.