A seven-month-old baby boy was thrown in front of a double-decker bus by a teenage girl in an unprovoked attack.
The child was snatched from his 13-year-old sister's arms and hurled into the road outside West Croydon station in south London, on 27 July.
The bus stopped before hitting the child and he suffered only minor bruising and scratches.
A 14-year old girl was arrested on suspicion of assaulting the baby.
She was also held on suspicion of assaulting the baby's sister and his 33-year-old mother.
The girl has been bailed by police until 2 September pending further inquiries.
Police are still looking for a second teenage girl who took part in the assault.