Lincolnshire Police are looking for information after two 13-year-old boys were assaulted in Lincoln.
The incident happened on July 12 at about 8.45pm on Dixon Street.
The boys were walking along the road when one was approached and pushed over by a man.
The boy was taken to Lincoln County Hospital with a head injury, where he got stitches and also treatment for a broken wrist.
The other boy was also assaulted by the man, but he was not injured.
Police are looking for information about the man who carried out the attack so they can get in touch.
He is described as white, 6 foot tall, and of a muscular build, with short hair. He was wearing a T-shirt and possibly shorts, with a logo on the back.
Anyone with information should contact Lincolnshire Police on 101 quoting incident number 490 of July 12 or Crimestoppers on 0800 555 111.