Detectives have issued details of a teenager they want to speak to in relation to the murder of a butcher in his own shop - and also announced a �10,000 reward for information leading to the prosecution of the culprit.

Irfan Ahmad, of Hanley Road, Finsbury Park, was stabbed in the chest with one of his own knives on September 29 at the shop where he worked. Mr Ahmad, 24, is understood to have stepped in to diffuse an argument between a man and a phone card seller based at the front of the store, Halal Food Direct in Wood Green. He died at the scene.

Shahie Ali, the shop’s owner, said: “I hope this reward will help bring Irfan’s killer to justice. There was much support from the community after the event and we’re still very saddened by his loss.”

Police are looking for Ehsannullah Mohabat, 18, who was seen leaving the store shortly after the incident, which happened at around 3pm.

Officers say Mr Mohabat returned to his home in Enfield before disappearing, and believe he has contacts in Enfield, Haringey, Redbridge, Barnet, Waltham Forest and Brent, and in the Gloucester, Leicester and Birmingham areas.

Det Ch Insp Steven Lawrence, leading the investigation, said: “Mr Ahmad was killed in a busy area, in the middle of the afternoon and we need to hear from any witnesses who have not yet come forward. Do you have any information about the murder or the whereabouts of Mr Mohabat?

“It is essential that anyone with information contacts us as soon as possible.”

Mohabat is described as 5ft 5ins tall and at the time of the stabbing was wearing a black hooded top with red writing on the front, baggy grey trousers and black trainers.

Anyone who can help should call the incident room on 020 7321 9290 or to remain anonymous, Crimestoppers on 0800 555 111.