A 12-year-old girl was raped in a leisure centre changing rooms by a boy believed to be aged 15, police said.
The attack took place at Temple Park Leisure Centre in South Shields on December 9 last year - but details of the incident have only now been released by police.
The girl met the suspect on a bus journey from South Shields town centre.
The pair got off the bus and walked together to Temple Park Leisure Centre on John Reid Road where the incident took place in a changing room between 2.35pm and 2.45pm.
Detective Inspector Christina Barrett said: "Offences of this nature on a young victim are uncommon, particularly in a public place.
"People can be reassured that we are doing everything we can to trace the person responsible.
"We appeal for the public's help and would urge anyone with information or who recognises the person from his description to come forward.
"All calls will be treated in the strictest of confidence."
The suspect is white, approximately 15-years-old, 6ft, slim, with brown eyes and brown short spikey hair and was wearing a diamond earring in his left ear.
He was wearing black Lacoste tracksuit bottoms with white stripes down the side, a pair of blue/black Nike trainers, blue knee-length football socks and a white and blue horizontal striped short sleeved polo shirt with a Fred Perry logo on the chest and a blue collar.
A South Tyneside Council spokesman said: "Temple Park Centre is accredited by Leisurewatch, a scheme to help protect children.
"Leisurewatch also provides training for staff with systems in place for the reporting and monitoring of incidents.
"The changing rooms are staffed and were staffed at the time of the alleged incident.
"We are doing all we can to help the police with their investigation and would urge anyone with information to contact them."