The 23-year-old Black man died after paramedics administered the powerful anesthetic during a confrontation with police.
The Department of Public Health and Environment, which certifies emergency medical responders, said in a statement Wednesday that it's investigating "numerous complaints" that provided new information "regarding a ketamine administration in August 2019."
Ketamine has been used illegally as the club drug Special K. The medication, which is used in hospitals primarily as an anesthetic, generates an intense high and dissociative effects.
McClain's death is one of several cases to receive renewed scrutiny after the police killings of George Floyd, Breonna Taylor and other African Americans sparked massive protests across the country.
On August 24, 2019, McClain was stopped by three White officers from the Denver suburb of Aurora as he walked home from a convenience store. A 911 caller had reported a "suspicious person," according to a police overview of the incident.
McClain resisted officer contact, the report said, and there was a struggle. On an officer's body camera, McClain was heard saying, "I'm an introvert, please respect the boundaries that I am speaking."
McClain was heard telling the officers he was trying to stop his music to listen to them when they began to arrest him. One officer was heard telling another, "He just grabbed your gun, dude."
The video showed an officer wrestle McClain to the ground.
At one point, an officer told McClain, "If you keep messing around, I'm going to bring my dog out and he's going to dog bite you."
One officer placed McClain in a carotid hold, or chokehold, and he briefly lost consciousness, according to the report. When they released the hold, McClain began struggling again.
Paramedics arrived at the scene and administered ketamine to sedate McClain, the report said. McClain suffered a heart attack while in an ambulance, and he was declared brain dead three days later, according to a letter from the district attorney.
An autopsy did not determine a cause of death but listed intense physical exertion and a narrow left coronary artery as contributing factors, according to the police overview. The coroner found the amount of ketamine in his system to be a therapeutic amount.
The Adams County district attorney, Dave Young, declined to file criminal charges against the officers at the time. In February, a police review board declared that the use of force in the altercation, including the chokehold, "was within policy and consistent with training."
The officers were placed on administrative leave following McClain's death but later reinstated after prosecutors declined to file charges.
In June, Gov. Jared Polis responded to public outcry by announcing that his administration was reexamining the case.
"Elijah McClain should be alive today, and we owe it to his family to take this step and elevate the pursuit of justice in his name to a statewide concern," Polis said in
