A public inquiry into a 2017 terrorist attack in Britain is the last opportunity to track down the people who helped two brothers carry out a deadly suicide attack at a crowded concert venue, a police lawyer said. Salman Abedi triggered a shrapnel-filled rucksack bomb in the foyer at an Ariana Grande concert in Manchester, killing 22 people including children. His younger brother Hashem was jailed for life in August. At the time of the attack, Hashem was in Libya, where their parents were born, but helped Salman to prepare the bomb. Hashem is believed to have been one of the last people to speak to his sibling before the May 22 explosion. A police lawyer told the inquiry on Tuesday that the Abedis must have had technical and financial help with planning the attack. The dead man’s family have declined to help the inquiry, which started last month in Manchester. “What of the other potential murderers?” said Patrick Gibbs, a lawyer representing the British Transport Police, which is responsible for the security of the UK’s transport network. “We don’t yet know their names but … it will have been obvious, I suggest to all of us, that those brothers did not act alone. “They must have received technical help and financial help and training and support from other people. “Other people must have known, or at least suspected, what they were up to and those other people are at large.” Mr Gibbs said the “mountain” of money spent on the inquiry would have been well spent if “one or more of those accessories to mass murder” could be run to ground. “Put another way, your inquiry, I suggest, is probably our last opportunity to track down those without whose help and inspiration these murders could not have been committed,” he said. The inquiry is expected to continue for months into 2021 and has already heard of the brothers’ links with convicted terrorists in the UK. Salman Abedi, 22, carried out the attack with a home-made bomb at the end of the concert by US pop star Ariana Grande as parents gathered to collect young fans. Hundreds were also hurt as shrapnel blasted across the foyer, leaving many with life-changing injuries. The Abedi brothers, who were born in Britain, were collected weeks before the attack by their parents and taken to Libya. Police believe the family was told about the extent of their sons’ radicalisation. Salman managed to return alone to the UK within days and put into place the final preparations for the attack.