A man doused himself with what appeared to be lighter fluid and then set himself ablaze while handcuffed and interacting with police officers in Denver’s Civic Center park on Thursday afternoon, authorities and witnesses said.

The man, engulfed in flames, then ran several hundred feet as officers and bystanders tried to put the fire out. He was taken to a hospital in critical condition.

Witnesses say the incident began about 1 p.m. after a civilian Denver Police Department employee was in the park and saw the man pouring a fluid on himself. The employee called police dispatch to request officers to check on the man.

Responding officers quickly made contact with the man, police say,  and were in the process of placing him into protective custody — he had just been placed into handcuffs — when suddenly the man became engulfed in flames. A witness told the Denver Post the man started the fire with a lighter.