A teenage girl was attacked in Portslade at around 1.20am today (Friday 3 September).
The victim, 17, suffered superficial injuries after the man tried to grab hold of her and pushed her against a wall before he ran off north along Mill Lane.
Detective Constable Amanda Payne, of Sussex Police, said: “The victim has been left very shaken by the attack.
“The man’s intentions are unclear and detectives remain open-minded to the possibility the attack was either an attempted robbery or sexually motivated.
“He was interrupted by a passing car and I am keen to trace this driver, who may hold important information.”
The suspect is described as black, 5ft 6in, slim, with a broad build, aged 20 to 30 years old, with rough shaven hair and stubble. He was wearing a black hoodie and jeans.
Police have made an arrest and an interview was due to take place this afternoon or evening.
Anyone with information about this morning’s attack is asked to contact Sussex Police on 0845 6070999 or to call the independent charity Crimestoppers anonymously on 0800 555111.