British police have issued an arrest warrant for the brother of the Manchester Arena bomber Salman Abedi - so they can haul him back to the UK to face trial for murder.

Hashem Abedi, 21, is thought to be in Libya held captive by the militia group RADA.

Detectives believe he is being held at the airport in the capital Tripoli or one of two bases in the east of the city.

Hashem Abedi, 21 (pictured), is thought be in Libya with the militia group RADA, a radical Islamist special operations military police

Twenty-two-year-old Salman travelled with Hashem to Libya from the UK the month before he would return to detonate explosives in the lobby of the Manchester Arena during an Ariana Grande concert killing 22 and injuring 500 on May 22 last year.

Hashem remained in Libya where his parents were born while Salman returned home to carry out the attack.

Greater Manchester chief constable Ian Hopkins told the Mirror he is determined to find Hashem and bring him back to the UK to stand trial.

Salman Abedi (pictured) returned to the UK while Hashem stayed in Libya, detectives believe

Police say they have enough evidence to charge Hashem with 22 counts of murder, attempted murder and conspiracy to cause an explosion.

It is understood no similar request was made to extradite the Abedi brothers' father Ramadan - who is also understood to have been arrested by militia.

Andy Burnham, Mayor of Greater Manchester, said: 'I have consistently said it is imperative that any trial related to the Manchester Arena attack takes place in the UK.

'I want to thank Greater Manchester police and the Government for their hard work in getting us to this point on behalf of the people of Greater Manchester and all those affected by this appalling act of evil.'

Labour's Andy Burnham, Mayor of Greater Manchester, said it was 'imperative' Hashem Abedi was tried in the UK

Abdallah Forjani (second from left), the cousin of 22-year-old suicide bomber Salman Abedi (right), said he thinks Abedi is being tortured in Libya

Hashem's cousin Isaac Forjani, who lives in Fallowfield, Manchester, said: '[Hashem] is in prison [in Libya] now being tortured. He has been beaten up quite badly by the people holding him.

'I don't care what happens to him now. If he had anything to do with Manchester then I hope he rots in hell.'

Detectives think Hashem will only be released if the UK pursues him through diplomatic channels.

They also admit the investigation could remain ongoing for 'years to come' as Libya remains in the midst of civil war after the death of Colonel Gaddafi.

An extradition treaty was agreed between the UK and the Great Socialist People's Republic Libyan Arab Jamahiriya in November 2008.