A teenage girl was sexually assaulted as she walked home from school.
The 14-year-old was walking through Crookes when she was attacked in an alleyway off Cross Lane.
An E-fit of the attacker has been released.
A South Yorkshire Police spokeswoman said: "At around 3.05pm on Friday, July 15 it is reported that a 14-year-old girl was walking home from school and was going through an alleyway off Cross Lane, Crookes, when an unknown man is believed to have sexually assaulted her.
"The girl ran home and notified her parents, who called police.
"The man is described as being white, around 5ft 8ins tall, of stocky build. He was reportedly wearing a burgundy zipped hooded top.
"Do you recognise the man in the e-fit image? Did you witness the incident on Friday afternoon?"
Anyone with information should call South Yorkshire Police on 101 or Crimestoppers on 0800 555 111.