CROWN POINT, Ind. (WTVO) — Prosecutors have formally requested state police to investigate a July 27 incident in which several police dogs died from heat-related injuries in Lake Station, Indiana as they were being transported from O’Hare International Airport.

Lake County Prosecutor Bernard Carter requested the Indiana State Police to conduct an outside investigation into the incident last week following pressure from People for the Ethical Treatment of Animals (PETA), according to the Times of Northwest Indiana.

The K9s received medical attention at a gas station in Lake Station, Indiana.

The animal rights group had requested a state police investigation independent of Lake Station Police in early August, citing a conflict-of-interest between Lake Station Police Chief James Richardson and the owner of the company used to transport the K-9s

PETA also criticized Lake Station Police’s handling of the incident, claiming the department “inexplicably blocked dying dogs from receiving emergency veterinary care” from the Humane Society of Hobart.

Approximately 20 dogs were en route to a training facility in Michigan City when the truck’s cargo area air conditioner failed in the midst of a traffic jam, causing the dogs to swelter in dangerous heat for hours.

Eight of the dogs succumbed to heat-related injuries in Lake Station, about 35 miles outside of Chicago.

“There were already several dogs dead on the scene, and multiple failing fast,” said Jennifer Webber, executive director of the Humane Society of Hobart, according to the Associated Press. “Their crates inside the truck were completely trashed on the inside, and the little water bowls were the size you’d give a parrot. And they were empty and torn up as if the dogs were exasperated.”

The dogs were held in crates located in the cargo area of the truck.

Though Lake Station Police concluded the incident “was not an act of animal cruelty or neglect but a mechanical failure of the AC unit that was being used in the cargo area,” Weber said she encountered resistance when attempting to gather information.

On August 23, PETA supporters gathered outside Lake Station City Hall to protest officials response to the incident.

A week later, the Lake County Prosecutor’s Office confirmed it had requested a state police investigation into the deaths.

“Nothing can bring back the dogs who slowly baked to death inside an airless, hot truck, but this is a step in the right direction toward ensuring that those responsible for their terrible suffering are held accountable and that preventative measures are put in place to avoid a devastating repeat,” said PETA Senior Vice President of Cruelty Investigations Daphna Nachminovitch in response.