A body was found at a flat in York after police were alerted to a man seen with blood on his hands at the city's railway station.
Officers acted over concerns about the behaviour of the man and later arrested a 19-year-old in the Scarcroft Road area in the early hours.
The victim, who was in his 50s, was later found at the flat on Holgate Road.
A murder investigation is under way and police inquiries are continuing.
A North Yorkshire Police spokesperson said: "Scene guards were in place at locations across the city including the scene of the murder at the flat in Holgate Road, a bus stop outside York Railway Station and a taxi rank on Queen Street.
"Officers remain at the flat this morning as the investigation continues."
The force said it was not yet in a position to release the victim's name.
Detectives have appealed for witnesses and in particular "anyone who saw any suspicious activity" in the area of Holgate Road between 23:00 GMT on Sunday and 03:00 on Monday.
The man remains in police custody for questioning.
