THE family of murdered Oxford police station cleaner Enayit Khalili have marked the first anniversary of his death with a fresh plea for people to come forward.

And police have increased the £5,000 reward for information to £25,000.

Mr Khalili, 26, was stabbed in the stomach and later died after he answered the door to the killer at his home in Fiennes Road, Rose Hill, a year ago today.

His cousin Hassan Mohammadi and brother Sedigh Mansoorian say their family - living in Oxford, Pakistan and Afghanistan - have been through 12 months of pain.

They described Mr Khalili as a hard-working family man who left behind a grieving wife in Pakistan. And they pleaded with anyone who had information that could solve the murder to come forward.

Mr Mohammadi said: "The past 12 months have been very shocking and very painful for the family.

"He was a hard-working man, who worked hard to be a good family man and a good human being. He loved his family.

"I don't know why anyone would kill Enayit."

Mr Khalili, an Afghan, came to Britain in 2001 seeking asylum. He later received permanent leave to remain in the country.

In the months before he was murdered, Mr Khalili worked as a cleaner at Cowley police station and was known to many local police officers.

Mr Mohammadi added: "The family is happy with the way police are looking into the case, but we want the police to publish why Enayit died - and who has done it.

"It is important for us to know who killed Enayit.

"We would like to appeal to anyone who might know any information that might help find the killer, to contact the police.

"We hope the killer will be found one day - and that police will bring him to justice.

"We are all suffering and in pain."

While working in England, Mr Khalili sent back some of the money he earned to his family in Afghanistan and Pakistan.

He was well known at bookmakers in Rose Hill and Cowley and also visited Rileys Snooker Club, in Between Towns Road.

He worked part-time as a waiter at the Oxford greyhound stadium, in Cowley, and was a regular at Marsh Park, off Cowley Road, where he was the founder of a volleyball team.

Mr Khalili was also a frequent visitor to the gyms at Blackbird Leys Health Centre and the greyhound stadium, where he practised martial arts.

Det Insp Colin Seaton said: "It has devastated his family and shocked not just the Afghan community but all communities in Oxford and further afield."

Police still do not know why Mr Khalili was killed.

But detectives are optimistic that by offering an increased reward of £25,000 for information, his killer will soon run out of places to hide.

Since his death, more than 50 police officers have been on the trail of his killer.

They have followed more than 850 lines of inquiry, searched more than 400 addresses, collected 1,350 exhibits and taken about 400 statements.

Officers have also interviewed everyone known to have had contact with Mr Khalili.

Det Insp Seaton said: "We don't know why Mr Khalili was killed.

"But I do feel there are people out there who have information.

"I appeal for that person to come forward, because it might be that little bit of information that solves this case."

One lead pursued by police was gambling debts Mr Khalili owed to friends and associates. But the debts are not being treated as a major factor in his death.

Five associates of Mr Khalili, seen on CCTV speaking to him in an Oxford bookmakers in the days before his death, have been interviewed and are not suspects.

But police said they were keeping an open mind to any potential motive and are not ruling out any line of inquiry.

Mr Seaton added: "We did have some information in relation to the initial reward.

"This significant increase will serve as a message that the information we want is extremely useful to investigating and finding who the killer is.

"This has has been a very challenging investigation from the outset. We can't rule out anything.

"I'm optimistic that we will find Mr Khalili's killer, with the help of the public."

In the days after the stabbing police arrested six men on suspicion of murder.

They were later released without charge and no one has been arrested since.

No witnesses to the stabbing have been found.

Last October, police offered a £5,000 reward for information, which has been increased to £25,000.

It is the joint highest amount ever offered in Oxfordshire.