The heartless killer's younger brother Hashem Abedi was arrested in the Libyan capital of Tripoli last night, while father Ramadam has also been detained today.
Hashem was arrested on suspicion of links with Islamic State, a spokesman for a local counter-terrorism force revealed.
Police claim he had prior knowledge of the attack and said he may have been planning his own atrocity.
The Libyan security force, known as Rada, detained Hashem Abedi, who was born in 1997, on Tuesday evening, spokesman Ahmed Bin Salem said.
Pictures on social media show the youth wielding a huge weapon while dressed in a Nike top.
Hashem Abedi has been arrested following the attack by his brother Salman Abedi
The father was seized by masked gunman while giving a TV interview.
A third brother has also been arrested after police raids in the UK.
Earlier today the Abedi brothers’ father spoke from Libya, where he said his son was innocent.
He said: “We don't believe in killing innocents. This is not us.”
Hashem Abedi following his arrest in Tripoli, Libya
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Ramadam Abedi, father of Hashem and Salman Abedi
Ramadan Abedi fled Tripoli in 1993 after Moammar Gadhafi's security authorities issued an arrest warrant and eventually sought political asylum in Britain before settling in Manchester.
He then returned and is now the administrative manager of the Central Security force in Tripoli.
Sickening images reveal what's left of the Manchester bomb backpack
Wed, May 24, 2017
The remains of the backpack that killed at least 22 people, with more than 60 injured after Salman Abedi detonated a bomb in the Manchester Arena, at 10:30pm Monday, 22 May 2017
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12-volt battery that was possible power source
He said the 22-year-old sounded "normal" when the pair spoke five days ago and claims he was preparing to visit Saudi Arabia.
It comes after Salman Abedi killed 22 and injured around 100 at Manchester Arena on Monday.
This is a breaking story. More to follow…