The family of a teenager murdered in an execution-style 'hit' today appealed for an end to the reign of violence on Keighley's streets.

In the six months since Yasser Hussain Nazir was gunned down on the forecourt of a petrol station, three other young Asians have been killed in what are thought to be gang-related attacks.

Murder squad detectives said they are hunting the 'final piece of the jigsaw' to catch Yasser's killer - a move which the 16-year-old's family believe could restore peace to the town.

Today, Yasser's brother Mohammed Sadique, 24, said: "Losing him has ripped the soul out of our family. We have not been the same since. We all used to spend happy days together but they have gone since he died and I don't think they will ever come back."

Speaking from the family's home in Chatsworth Street, Mr Sadique said: "The police say they are very close to the people that did this and that they just need a bit more of information.

"We would appeal to anyone who knows anything to speak to them - and to help stop the violence in this town. If Yasser was here, he would want this all to stop. Our family want these killings to stop."

Mr Sadique, a production operative, said it was unclear if it was Yasser, or the two friends in his car, who were the target of the well orchestrated ambush.

"Yasser would not have done anything to provoke this. We all do silly things when we are young but he wasn't a bad lad."

"He was great son and brother to have around. He could have done anything with his life, he could have been anything. We will never know now."

Detectives have interviewed more than 300 people about the murder at the Shell garage in Haworth Road, Bradford, on September 5 last year. Although 15 people have been arrested and questioned, it remains the only case in the string of Keighley killings where no-one has been charged.

Yasser had just pulled into the garage when a gunman leapt out of a green Honda Accord and fired two shots into his car, both of them hitting him in the head.

Detective Superintendent Phil Sedgwick, who is leading the investigation, said: "We have suspicions as to who the killers are. We believe that up to a dozen may have been involved in the conspiracy to a lesser or greater extent.

"We are not far from prosecuting the offenders but we need that final piece of the jigsaw."

He said the public response had "not been as good as we hoped" and added: "I am sure that the identities of the killers are well known among certain sections of the community but that has not permeated to us despite our best efforts."

While officers have probed a number of possible motives, including retribution or drugs, they have yet to deduce exactly why Yasser died.

Anyone with information should contact detectives on (01274) 376225.