A cyclist attacked a bus driver in Hove and smashed the window of his bus.
The bus driver suffered a head injury in the attack and was treated by paramedics.
Police have urged witnesses to come forward.
Sussex Police said: “Emergency services were called to New Church Road at 1.10pm on Wednesday (25 June) to reports of a cyclist assaulting a bus driver.
“He had then ridden off in the direction of Portslade.”
The cyclist was described as a white man in his late twenties or early thirties, wearing a dark blue suit and carrying a leather shoulder bag. He was riding a white racing-style bike.
Anyone who saw what happened or has any information is asked to phone Sussex Police on 101 or email firstname.lastname@example.org.