A man wanted for the murder of an unarmed traffic policeman in Leeds was seen in Bradford city centre just hours after the shooting, police revealed today.

American-born Nathan Wayne Coleman was dropped off in Bank Street by a taxi driver who had picked him up from the Oakwood area of Leeds at 7.45pm on Boxing Day, four hours after PC Ian Broadhurst, 34, was shot dead.

And Coleman, 35, now thought to be clean-shaven, was also seen by members of the public in Bradford city centre on Saturday afternoon and Brighouse town centre yesterday lunchtime.

Speaking at a press conference at Killingbeck Police Station earlier today, Detective Superintendent Chris Gregg, who is leading the investigation, called for three possible key witnesses to come forward after Coleman was dropped off in Bradford's Bank Street.

"On the evening of the murder at 7.45pm a taxi driver picked up a man in the Oakwood area of Leeds. We believe this man to be Nathan Coleman. The taxi driver took him, at his request, to Bradford," Det Supt Gregg said. He asked the driver about bed and breakfast accommodation in Bradford.

"The taxi driver dropped him off in Bank Street in the city centre," Det Supt Gregg said.

"The taxi driver then saw him get into a black and white taxi parked nearby. We believe a young couple may have already been in the back seat of the car.

"We are appealing for that couple or the taxi driver to come forward."

Det Supt Gregg said Coleman, a nightclub doorman, could still be in West Yorkshire and staying in bed and breakfast accommodation.

Mr Gregg said officers were also examining footage from CCTV cameras in Bradford and Brighouse.

He added the taxi driver had found Coleman talkative and he mentioned he was from Selby.

He had said at the time the man believed to be Coleman was wearing a beige-coloured coat with a hood and carrying a rucksack, thought to be grey with two white stripes.

Detectives also revealed that ammunition and bullet-making equipment had been found.

Detectives involved in the inquiry had discovered an "bullet re-loader and component parts" along with a quantity of ammunition at a self-storage unit in Leeds. He agreed this could mean Coleman was carrying a substantial amount of ammunition if he was connected to the self-storage unit.

He said inquiries were continuing.

Mr Gregg said he had had a "good response" to yesterday's appeal with the incident room receiving 300 calls, many of which detailed possible sightings of Coleman.

PC Broadhurst died on Boxing Day when he was shot by a man who had been sitting in the back of his police car in Dib Lane, Leeds.

His colleague PC Neil Roper, 45, was shot twice by the same man and is still recovering in hospital.

Det Supt Gregg said PC Roper was recovering well.

A third officer, PC James Banks, 26, was also shot at but the round ricocheted off his radio belt and baton buckle.

The shootings happened after PC Broadhurst and PC Roper approached a stolen BMW in Dib Lane. PC Roper was about to handcuff the driver when he produced the gun.

Det Supt Gregg said today: "We are determined to find the killer of PC Broadhurst. The person who killed him is clearly a dangerous man. We need to question Coleman regarding that murder and we would urge him to come forward or anyone who knows him to come forward."

Coleman was a keen gambler and often went to casinos. He kept himself to himself and looked like he had good survival instincts, never seeming to be settled. He no longer has his moustache, police said today.

*Phone 0800 318001 with any information.