A distraught mother who has had two sons murdered in four years says she needs to look her second son's killer "in the face and ask why".

Lucy Cope, 47, made an emotional appeal for help in catching the killer of her 22-year-old son, Damian, who was shot outside Brown's nightclub in Holborn, central London, in the early hours of Monday.

In February 1998 another of Mrs Cope's sons, Sean, was stabbed to death outside her home in Walworth, south London.

His killer has never been found.

Lucy Cope: Killer must be found

During the appeal Mrs Cope said: "Damian looked into the eyes of a man with a gun who took his life - this man is out there and he must hand himself in.

"I need to look this person in the face and ask why he did it.

"They are cold-blooded murderers, they are out there and I know they did it and they know they did it.

"I'm not going to rest until they are brought to justice."

CCTV footage

Police believe that when Damian was in the nightclub he received a phone call on his mobile from someone he knew.

He went outside and walked to the junction of Great Queen Street and Newton Street, where he was shot once in the stomach with a small calibre handgun.

Damian managed to stagger back to the nightclub, but died six hours later in hospital.

Detectives said three cars were spotted near the murder scene - a black and a silver BMW and a Peugeot.

'Face to face'

Detective Inspector Tim Neligan said: "We are actively investigating this matter - the death of Damian Cope.

"So many people have come forward and given information anonymously, but we need to speak to them face to face."

Police are keeping an open mind as to the motive for the murder and are studying CCTV footage from the nightclub.

Mrs Cope, who described Damian as a football fanatic, said: "I am asking his friends, strangers, anyone who saw my child walk out of that club to his death to come forward and bring the person who killed my son to justice."