Police are treating a baseball bat attack on a 17-year-old boy by a gang as attempted murder.
The victim was knocked to the ground and beaten in Manchester Road, Reading, on Tuesday afternoon.
Police believe there had also been an earlier incident in Amity Road. The boy is in critical condition in hospital.
A boy aged 16, a girl aged 15 and a 21-year-old woman were arrested and bailed. A 23-year-old man was also arrested and remains in police custody.
Det Sgt Ali Driver, of Thames Valley Police, said: "This was a very nasty attack on a teenage boy, which has left him with serious injuries."
Witnesses, residents of the Newtown area of Reading, or anyone with information about the attack, have been urged to contact police.