Police are investigating five sex attacks on women in the Bilborough and Wollaton areas of Nottingham.
The first happened on 11 February in Cockington Road, Bilborough, with the latest on Sunday evening in the car park of Wollaton Community Centre.
In each case the attacker approached his victims on a pushbike before attacking them, said police.
He is described as black, in his early 20s, between 5ft 6in and 5ft 10in and heavily built.
Detectives said they were keeping an open mind as to whether the attacks were linked, but urged people to remain vigilant.