A man was stabbed in the head along a Washington bike path Tuesday afternoon, police said, and suffered life-threatening injuries.

The incident happened around 2:30 p.m. along a bike path in Kenilworth Park in Northeast Washington. U.S. Park Police said they received a call for a report of an assault.

When officers arrived they found a man suffering from “multiple stab wounds,” including one to the head said Sgt. Anna Rose, a spokeswoman with the U.S. Park Police. He was flown in a medevac helicopter to an area hospital with life-threatening injuries, she said.

Rose said it was not known what the man was doing in the park at the time of the attack and only a vague description of a black male suspect was given. She said officers searched the area for two hours with a K-9 unit and did not find the suspect.

The investigation is ongoing, she said.