With the summer still in full swing, and many areas reaching record-high temperatures, it’s more important than ever to be vigilant about dogs left in hot cars.

Dogs are extremely susceptible to heat stroke, and won’t last long if left in high-temperature cars. Even if you think you’ve taken precautions to prevent tragedy, accidents can still happen.

That was the tragic case recently when one police department K9 died after being left in a hot car after the air conditioning and emergency precautions failed to activate.

According to a release from the Arnold Police Department in Missouri, a 4-year-old K9 with the department named Vader died of heat exhaustion on July 31.

The department said that Vader was left in a running patrol vehicle with the air conditioner running, which they described as a “necessary and common practice” for K9s that are not actively engaged with police work.

However, when officers returned to the vehicle, they discovered that the air conditioning system had malfunctioned.

The department also said that their K9 patrol cars are all equipped with a failsafe system that notifies the handler, activates the alarms and sirens, sounds the horn, and rolls down the windows if the vehicle reaches over a certain temperature, but this emergency backup “failed to activate.”

Vader was rushed to the veterinary clinic, and while he initially showed “signs of improvement,” he later passed on.

“Unfortunately, we learned last night that there were no further treatments available for Vader and he succumbed to his injuries,” the Arnold Police Department wrote.