The recent death of a Tennessee sheriff’s office dog after being left in an outdoor kennel without water for a day and a half in excessive heat has prompted the animal’s handler to resign amid administrative and criminal investigations, according to authorities.

Bart had been a patrol dog specializing in suspect apprehension, tracking, searches and drug detection before his handler found him dead inside his outdoor kennel on 19 September, Julian Wiser, the Madison county sheriff, said in a social media video announcement.

A veterinary necropsy of the two-and-a-half-year-old German shepherd found that he had died of heatstroke due to severe dehydration, with investigators learning Bart’s handler at the Madison sheriff’s office had not been home for about 36 hours while temperatures climbed to 101F (38.3C) and water was inaccessible to the canine.

In his video addressing the case, Wiser called Bart’s death “unfortunate and preventable”, and the sheriff also described himself as a former canine unit supervisor.

“This is … very sad and unfortunate,” Wiser said in the video on Friday. “We depend on our canines to help keep our community safe and our law enforcement officers, but our canines depend on us to take care of them.”

Bart’s handler was neither immediately identified by Wiser’s office nor formally charged with a crime. Wiser said the deputy resigned after being placed on administrative leave.

The sheriff added that his office had also served search warrants in connection with simultaneous internal and criminal investigations into Bart’s death. Wiser said resulting findings would be forwarded to prosecutors.

A survey published in the Police Practice and Research Journal found heatstroke to be the second-leading cause of death for police dogs in the line of duty, behind only gunfire.

In fact, heatstroke was responsible for one in five such deaths, according to the survey.

“Being left unattended and mechanical failures overwhelmingly (70.6%) characterized these heatstroke deaths,” said an abstract of the survey, which studied information on more than 400 canine deaths listed on the Officer Down Memorial Page website.

According to the survey’s abstract, “Summer months were also significantly implicated in increasing the odds of line-of-duty heatstroke deaths.”