A 16-year-old boy has been arrested in connection with an attack on a 10-year-old girl who went missing for more than two hours, provoking a huge police search operation.
The girl, from Stockton-on-Tees, suffered "serious but non-life threatening injuries" during the incident on Saturday, said Cleveland Police.
She was taken to a specialist paediatric unit in Newcastle where she was being examined as more than 40 police and police staff worked on the investigation.
Cleveland Police said the alarm was raised at 6.30pm on Saturday when the girl went missing from her home. She was found in Maritime Way, Stockton, at 9pm by a member of public.
A force spokeswoman said she was taken to the Royal Victoria Infirmary, in Newcastle, where she remains. She said: "Initial inquiries suggest she had been the victim of a serious assault."
The 16-year-old was arrested at noon today in connection with the assault, she said.The spokeswoman said the search involved a number of specially trained search officers as well as a helicopter. An incident room has been set up with a staff of 48, she said. The girl is 4ft tall and has brown hair.
She added: "Police would particularly like to hear from anyone who saw a girl matching this description either alone or with someone else between 5pm and 9pm yesterday evening."
She was wearing black leggings and a chequered top, with a brown, furry body-warmer at the time. The spokeswoman said the team has been "working round the clock to establish who she was with and where she had been throughout the evening".
She added: "Police are asking the local community to work with them and remain calm."
Neighbourhood police patrols have been stepped up in the area, she said.