A woman was grabbed and then indecently assaulted as she walked near a children's playground in Brighton.
The victim, who is in her 20s, was walking along a footpath which runs between Goodwood Way and Birdham road next to the play area.
She was grabbed by a man who then dragged her a short distance and assaulted her.
Police said the offender ran off when the woman screamed.
'Isolated incident'
She was not seriously physically hurt but was left very shaken by the attack.
Detective Inspector Jane Tilsey, said: "We are treating this as an isolated incident and working hard to find this man.
"I'd urge anyone who can help our enquiry to come forward."
The attacker had shoulder length, dark, wavy hair which was unkempt and very greasy.
He also had a moustache and a few day's growth of a goatee beard.
At the time of the attack, which took place in the Moulscoomb area of Brighton in the early hours of Wednesday morning, the man was wearing baggy jeans and a t-shirt of a similar colour.
Police have been carrying out house to house enquiries in the area to try and find the attacker.