A teenager has been threatened, punched and sexually assaulted by a man in Bedford town centre.
The 18-year-old woman was attacked in the early hours of Sunday in Mayes Yard, police said.
She managed to leave the scene and get to the Corn Exchange where she raised the alarm.
It is thought the attacker, described as an Asian man in his 20s or 30s, left in the direction of Silver Street. Police are appealing for witnesses.
Officers believe the man might have been loitering in the area around Mayes Yard before the attack, and that people leaving the town's pubs and clubs in the early hours could have seen him.
Det Ch Insp Steve Collin from Bedfordshire Police said: "This has been a very frightening experience for the young woman and she has been left shocked by what has happened to her.
"This man needs to be found before he strikes again."