The hunt for the killers of a British teenager who was apparently murdered for his mobile telephone netted a fourth suspect. A 16-year-old boy was arrested in south London a day after police took two 16-year-olds and a 17-year-old into custody.

They have all been arrested in connection over the death of Kieran Rodney-Davis, 15, who was stabbed while on a afternoon shopping errand for his mother in Fulham, London last week.

Police said yesterday two of the youths had been released and bailed until August 9. Witnesses to the attack said they saw three teenagers wearing balaclavas or scarves fleeing as Kieran lay dying from a single stab wound to the chest just metres from his home.

Kieran’s mobile phone was not taken during the attack, even though police believe it was the motive for the attempted robbery. The site where the youngster died has been turned into a makeshift shrine by neighbours and school friends who have left flowers and messages of condolence.

The killing of Kieran in broad daylight has evoked memories of the murder of Damilola Taylor, 10, who was stabbed in the leg and bled to death on a housing estate in south London in November 2001. The government is under pressure to stem a rise in violent crime, which was 11 per cent higher in the last quarter of last year compared with the same period in 2002.

Police set up a special unit to combat a leap in mobile phone thefts last December. Half of all street crime in Britain now involves the theft of a mobile phone, according to crime statistics.