Seattle police arrested a man on investigation of homicide after a man was fatally stabbed in City Hall Park on Thursday night.

The 49-year-old suspect was booked into the King County Jail and is expected to make his first court appearance Saturday afternoon, according to jail records and the King County Prosecuting Attorney’s Office.

Witnesses called 911 around 8 p.m. Thursday and reported a man had been stabbed in the 400 block of Jefferson Street, according to the Seattle Police Department’s online blotter. The location is on the park’s eastern boundary, just south of the King County Courthouse, and is the site of a homeless encampment.

Officers arrived within two minutes and arrested the suspect, who was still holding a knife in his hand when he was contacted, says the blotter item.Police located the victim, in his 30s, and started CPR, but he was pronounced dead at the scene, it says.

Homicide detectives are conducting witness interviews and collecting evidence in an effort to determine what led to the stabbing, according to police.