Student Anthony Walker, 18, died in hospital after being attacked in Huyton, Merseyside, on Friday night.
Mr Walker had been taunted while at a bus stop on St John's Road with his girlfriend and a male cousin. They moved but were attacked in a park.
His girlfriend and cousin, both 17, ran to get help, but when they returned he was on the ground with head injuries.
'Unprovoked, racist attack'
Merseyside Police Assistant Chief Constable Bernard Lawson said: "What we are dealing with here is an unprovoked and vicious attack on a young black man which we believe to be racially motivated.
"This was a despicable act and we're absolutely determined to find the people responsible.--