POLICE said this afternoon that they had traced one of three men they want to speak to following the murder of Enayit Khalili.

The details of the men were released to media on Tuesday and one of the men - shown in the bottom image - has since come forward and spoken to the police.

Police said today he had been 'very helpful' in assisting detectives with their inquiries.

Mr Khalili, a cleaner at Cowley police station, died after suffering a single stab wound when he answered the door of his home in Fiennes Road, Rose Hill, Oxford, in March.

Det Insp Colin Seaton, from the Major Crime Unit, said: "We are still keen to speak to the other men in the images and would like to stress they are not suspects in the inquiry but witnesses.

"However, it is important that we speak to them because they could hold vital information.

"I would urge these men to come forward, or if anyone knows who they are, then please get in touch with us."

In an effort to get more people to come forward, Thames Valley Police are offering a £5,000 reward for any information that leads to the arrest and conviction of Enayit's killer.

Thames Valley Police have also set up a dedicated telephone line (07796 091 235) where people can leave messages in Dari, Enayit's native tongue.

There is also an email address for the investigation, enayitmurder@thamesvalley.pnn.police.uk Anyone who knew Enayit or has any information about his murder can also contact the Police Enquiry Centre on 0845 8 505 505.

If you do not want to talk to police and don't want to leave your name call the Crimestoppers charity on 0800 555 111.