The Manchester attacker reportedly called his mother and brother just 15 minutes before he blew himself up.
Salman Abedi asked his mother to "forgive me", a Libyan anti-terror offical said.
His father and brother have now been arrested in Libya, with the latter confessing to know "all the details" of the terror plot.
A spokesman for the Libyan government told The Times Abedi's brother, Hashem, told interrogators the attacker had phoned his family a quarter of an hour before the attack.
Hashem is alleged to have links to Isis, who claimed responsibility for the Manchester Arena attack.
“He also called his mother and brother 15 minutes before the operation started,” the spokesman said.
It comes after it emerged British counter-terror agencies missed several opportunities to stop Abedi before he carried out the Manchester Arena bombing.
Abedi's parents warned authorities he was "dangerous," a US official has claimed, and persuaded him to come to Libya and confiscated his passport.
But the 22-year-old persuaded his parents he was getting ready to visit Saudi Arabia for a short Umrah pilgrimage.
It is reported he in fact came back to the UK, via Germany, from Turkey four days before the bombing.
A German magazine reported that he came through Duesseldorf, and said he had not been on any international watch list.
“The father had all the passports with him and was holding them. But Salman said he wanted to do Umrah and that is why he needed to leave Libya," Jamal Zubia, a leading figure in the Libyan community in Manchester, told The Times. "His mother was happy.”
A family friend in Manchester, Lobna Elghriani, said: “They gave [the passport] back because he said he wanted to do Umrah.
"Then he came here. They were very worried. The father was very upset.”
Abedi's father said he sounded "normal" when he spoke to his family from Manchester five days ago and had promised to fly to Saudi Arabia.
Mr Abedi said he believes his son is innocent.
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