Photographs of a 16-year-old boy wanted in connection with a gangland killing were broadcast on a giant screen in the city where the shooting happened.

Detectives took the unprecedented publicity step - also naming Moses Mathias and offering a £15,000 reward for information leading to his arrest - after failing in a four-month quest to track him down.

Huge images of the wanted youth were beamed onto the wall of a building in central Manchester and also shown on a large screen in the city centre.

He is a prime suspect in the murder of Giuseppe Gregory, a 16-year-old schoolboy who was shot in the head as he sat in a car outside a pub in the Stretford area of Manchester.

Moses, who has a distinctive tattoo on his left arm, is from south Manchester but may be hiding in the West Midlands. Police warned the public not to approach him.

Giuseppe’s death, on a Sunday night in May, was the first fatal shooting in Greater Manchester for 16 months.

The killing was said to have been linked to gang activity and Giuseppe was known to associate with members of a south Manchester street gang, the Doddington Crew.

Though he had been shot in the leg previously, when he was aged 13, he was not a member of the gang himself and police do not believe he was the intended target of the shooting.

Giuseppe had been involved in minor crime in the past and his family, warned by police in November last year that he was keeping bad company, had tried to seek help for him.

He and his mother had been attending meetings with a key worker linked to a multi-agency team tackling gang-related problems. The boy, according to police, had turned his life around and was “really getting stuck into his school work”.

Three masked men entered the crowded Robin Hood pub in Stretford during a music event shortly before the murder.

They took a gold chain from a customer and then fired at the car Giuseppe was in as it sped away from the car park. One bullet went through the vehicle’s back window and hit him in the head.

A youth aged 17 and four men have been charged with a range of offences in connection with the murder, but Detective Superintendent Paul Rumney said yesterday that police were particularly anxious to speak to Moses, who was only 15 at the time of the shooting.

“We need to speak to Moses urgently. If anyone knows him or his whereabouts, you must get in touch immediately,” he said.

“We’re so keen to speak to him that we have taken the unusual step of naming a boy who is under 18 and we are offering the reward to anyone who can tell us where he is staying. That’s all you need to do.

“Giuseppe’s murder left his family and friends absolutely devastated and we will not rest until those responsible are brought to justice.” Greater Manchester Police have never before named a wanted juvenile who is a major crime suspect Mr Rumney said: “He is a very strong suspect, a compelling suspect. I believe he is dangerous.”

Times Recommends

• Sam and Kate's marriage over? That’s showbiz
• How Victoria Beckham beat the fashion snobs
• Why Too Poor for Posh School made me weep