teenager accused of two gang murders at the age of 16 has been sentenced to a life term. Jordan Williams was told on Thursday he would serve a minimum of 18 years for murdering Daniel Graham, 18, who was stabbed 24 times in 45 seconds. Williams, who turned 17 last month, was part of a gang which attacked Graham as he stepped off a bus on 29 January last year. Williams was later arrested for the murder of promising athlete Sylvester Akapalara, 17, who was shot dead in Peckham, south London, a month before. But a jury cleared him of that killing, which resulted in Sodiq Adeojo, 20, being jailed for a minimum of 30 years, also on Thursday. Williams, Colin Aghatise, 16, and Lennie John, 24, all from Peckham, were found guilty on Wednesday at the Old Bailey of murdering Graham. Williams and Aghatise were ordered to be detained during Her Majesty's pleasure, with Aghatise given a minimum term of 15 years. John, 24, was jailed for life with a minimum term of 22 years. They were said to be members of the GMG gang, which is said to stand for various names, including Guns, Murder and Girls. Graham was attacked with knives and a broken bottle in front of horrified passengers as he got off a bus in East Dulwich, south London. He was helped back on to the 176 bus by passengers, but died from his injuries. Judge Timothy Pontius told the defendants: "Daniel Graham was murdered in circumstances of horrific and merciless brutality. "He was killed in an attack which, for all its brevity, was intensely ferocious. "At least four, and probably more, played an active part. They were acting like a pack of hyenas." Williams had taken one of two lock-knives he kept at home to a party where violence was likely to arise at the meeting of two opposing groups. Williams and Aghatise were both 15 at the time. All three defendants were from decent homes and had good academic achievements. But on the night "they all too readily followed the pack instinct". The court was told that Williams was a server at his local church and had been elected chairman of his school council. And John's mother was said to work at a central London magistrates court. Duncan Penny, prosecuting, said trouble flared at an under-18s event at Dulwich Hamlet football club and a gun was fired, hitting a youth in the leg. He said a row broke out between Graham's friends and another group of youths. Penny said: "Daniel's group was punched and knives were produced and it appears a firearm was discharged and at least one shot was fired. "Daniel's group fled the party and their escape route took them past East Dulwich railway station. They were pursued by members of the defendants' group." Graham had tried to take refuge on the double-decker bus before changing his mind and jumping off. But he was attacked in front of passengers by a large group of youths who subjected him to "a volley of punches, kicks and stamps" to the body and head. Penny said CCTV on the bus showed the time of the attack as 12.09am. "It lasted in the region of 45 seconds," he added. "In that short period he had received 24 stab wounds, having been descended upon by a group of murderers." Passengers made the driver drive off while Graham, who was covered in blood, was laid across two seats by a nurse and her sister. After seeing some of the attackers at the next stop, the bus drove on until police and an ambulance reached it in Lordship Lane. Williams and John were identified by a youth who had viewed them rapping on YouTube. Aghatise's DNA was found on a broken bottle with Graham's blood on it. Graham had gained seven GCSEs and was doing business studies. He did voluntary work for the NSPCC children's charity in his spare time. His mother, Stephanie, said in an impact statement to the court that she had been devastated by his death. She added: "Everyone loved Daniel. He was instantly likeable to all who knew him."