Lincolnshire Police are appealing for witnesses following a sexual assault on Doddington Road in Lincoln on Sunday.
A woman was walking along Doddington Road, close to the junction with Newark Road, at around 12.20pm on June 2 when she was approached by a man on a pedal cycle.
As he was passing, the man slapped her bottom with his hand before cycling away. He turned left onto Newark Road towards the Rookery Lane junction.
The man is described as white, around 19 years of age, with ginger/blonde hair.
He was about 6ft tall, wearing grey camouflage knee length shorts, white trainers and a navy blue body warmer. He was also seen to be carrying a black rucksack and a cycle pump.
Anyone who witnessed the incident or who saw a cyclist meeting this description in the area at the time is asked to contact PC Tom Richardson by calling 101 and quoting incident 198 of June 2, 2013.