Police are trying to track down a passer-by who bravely intervened to help a teenager who had been robbed in a Leeds churchyard.
The 17-year-old victim was just inside the grounds of St John the Evangelist Church, in New Briggate, when he was approached by a thief who took his Nokia phone.
He then tried to take the victim's bag, but he managed to break free.
When the passer-by tried to intervene, the thief took out a small folding pocket knife and threatened him before making off.
PC Mark Wherrett, of Leeds District Crime Team, said: "We have been carrying out a range of enquiries since the incident, including checks on CCTV in the area, but we have not yet been able to identify the suspect.
"We would like to hear from anyone who witnessed the incident, particularly the member of the public who intervened at the time."
The suspect is described as white, aged in his early to mid twenties, about 5ft 9ins, medium build, with black hair and a pale complexion.
The robbery happened around 4pm on Wednesday, January 25.