Police in Detroit, Michigan, are investigating whether exposure to a drug sometimes used as a horse tranquilizer caused an officer to collapse during a routine crime scene investigation.

A Detroit Police public information office representative said officers responded to a call from a business owner concerning a man who’d been shot and stabbed on Oct. 3. Investigating officers called for assistance from a hazardous materials team after a controlled horse tranquilizer drug was allegedly found in the man’s possession, the representative said.

During the investigation, a supervising officer collapsed after coming in contact with the substance and was transported to a nearby hospital for treatment.

“We are still trying to identify the drug,” the representative said and declined further comment.

Terry Stevens, PharmD, a member of the Tennessee Commission on Pain and Addiction Medicine Education and a former pharmacist for the University of Tennessee College of Veterinary Medicine, in Knoxville, said ketamine and/or xylazine, both routinely used as veterinary tranquilizers, could have been the substances connected with the incident.

Veterinarians use ketamine as a sedative. Outside its intended use, people also use it as an incapacitating agent that renders a person vulnerable to a drug-facilitated sexual assault, Stevens said.

“The street name is ‘Special K,’ ” he said.

Likewise, people have also started using xylazine outside its intended use to calm horses before certain procedures such as stitching wounds, Stephens said. “On the street it is used in combination with other drugs such as heroin to (enhance) the effects of the drug,” he said.

The incident remains under investigation.