Since the Monday night bombing of Ariana Grande’s concert in Manchester, the deadliest attack in Britain in more than a decade, police forces have been searching for co-plotters of the terrorist attack. They have already determined the identity of the suicide bomber, Salman Abedi.

Abedi, 22, was a college dropout who was recruited by the Islamic State possibly two years ago. Though born in England, Abedi was of Libyan descent. In 1993 his family moved from Libya to Manchester, joining many others fleeing the regime of Libyan dictator Col. Muammar el-Quaddafi.

According to Nazir Afzal, former chief prosecutor for northwest England, Manchester now has one of the largest Libyan communities outside of Libya. Following the violent overthrow of Col. Quaddafi in 2011, it has continued to grow as ISIS and other extremists groups gain support in Libya.

Abedi had just visited in family in Libya last month.

The bomb that Abedi used may have been hidden in a blue backpack, according to forensic photographs from the blast site. It was made to inflict major shrapnel damage and even included a backup detonation system.

Consequentially, the bomb killed 22 people, including an 8-year-old girl. It injured at least 64 people as well, a third of them critically. Many of the victims were teenagers and young girls, along with their parents, who were major fans of Grande.

Following the deadly explosion, Grande officially canceled all of her European tour “Dangerous Woman” concerts through June 5. She also asked her fans to support “all those families affected by this cowardice and senseless act of violence.”

Abedi’s father admitted that Abedi had been troubled by the murder of his friend Abdul Wahab Hafidah in May 2016. Gang members most likely killed Hafidah.

However, Abedi’s father asserted that the bomber was not his son. “His ideas and his ideology were not like that,” he stated. “He was a man and I trust the man that he was.”

Nonetheless, several people who knew Abedi’s family contradicted his father’s account. They stated that a few years ago Abedi expressed approval of suicide bombing after an in imam at his mosque delivered a sermon condemning terrorism. Abedi became quite angry, causing neighbors to call an antiterrorism hotline.

An anonymous source also revealed that Abedi’s parents, who moved back to Libya after Col. Quaddafi’s downfall, had become worried about his radicalization. They took away Abedi’s British passport; however, they returned it to him when he expressed his desire to visit Mecca. Abedi instead used the passport to return to Britain.

Gérard Collomb, the French interior minister, further stated on Wednesday that Abedi had “most likely” gone to Syria and that his links to ISIS were “proven.”

With the bomber being identified, police are now looking for people who helped Abedi to carry out the bombing.

“It seems likely -possible- that he wasn’t doing this on his own,” said Amber Rudd, Britain’s home secretary to the BBC. Abebi’s bomb “was more sophisticated than some of the attacks we’ve seen before.”

According to Chief Constable Ian Hopkins of the Greater Manchester Police, “there’s an extensive investigation going on, and activity taking place across Greater Manchester.”

By Thursday Manchester police had put eight men in connection with the bombing into custody, including Abedi’s older brother. A woman had also been in custody; however, she was later released without charges.

As the search for more accomplices continues, Special Deterrence Forces have arrested Abedi’s father, as well as his younger brother, Hashem Abedi, in Libya.

According to a Facebook post made by the Special Deterrence Forces, Hashem had been a member of ISIS and had ties to the Manchester bombing. He was on his way to withdraw 4,500 Libyan dinars when the militia arrested him on Tuesday night.

Hashem had also traveled from Britain to Libya on April 16, and had been planning an attack in Tripoli, according to the militia. He spoke with his older brother on the phone daily, presumably to plan their terrorist acts.

Nonetheless, the militia’s statements about Hashem have yet to be confirmed. Though the Special Deterrence Forces are affiliated with the Government of Nation Accord, which is backed by the United Nations, human rights groups have accused the military of abusing its prisoners.

In addition to Hashem, police have been pursuing multiple leads. It is possible that Abedi used a bomb made by someone else.

Authorities are also investigating Abedi’s relationship with Raphael Hostey, a British recruiter for ISIS. Hostey is believed to have died in a drone strike in Syria last year.

According to a senior American official, officials are a looking into Abedi’s ties to Abdul Baset Ghwela, a radical Libyan preacher whose son had joined ISIS and had died fighting in Benghazi, as well.

Officials have also started examining reports made by people who knew Abedi. Several of Abedi’s associates, including an imam at his mosque, had contacted the police as early as 2015, saying that Islamic extremists may have recruited Abedi.

Following the bombing, the British government decided on Tuesday to raise the terrorist threat warning to a critical level. Authorities fear that more bombs could soon be detonated in crowded areas.

According to Raffaello Pantucci, a terrorism expert at the Royal United Services Institute in London, numerous Libyans living in Manchester have had ties to terrorism. The Libyan Islamic Fighting Group, which has links to Al-Qaeda, recently had a contingent in Manchester. Several Libyans from Manchester have also fought in Libya and Syria.

Officials thus remain on high alert as the bombing investigation continues to unfold.