The third killer behind the London Bridge attack was identified Tuesday as Youssef Zaghba, a Moroccan-Italian man arrested last year on suspicion of trying to reach Syria — openly boasting to authorities that he planned to become “a terrorist” and with ISIS videos on his phone, according to reports.

The 22-year-old was stopped in Bologna, Italy, on March 15, 2016 as he was about to board a plane for Turkey with the apparent intention of joining ISIS jihadists fighting in Syria, Agence France-Presse reported, citing Italian media.

“I’m going to be a terrorist,” Zaghba bragged to security staff at the Bologna airport when asked why he was traveling to Istanbul, according to La Repubblica.

Despite also finding ISIS propaganda videos on his cell phone, authorities failed to uncover enough evidence of links to terrorism to prosecute him, and he was released.

Italian authorities said they tipped off Britain about his movements. They also notified British and Moroccan security services about his status as a potential militant, according to the reports.

But UK authorities insisted Tuesday they have no evidence their Italian counterparts shared any information about Zaghba, The Guardian reported.

Zaghba, who was shot dead along with his two accomplices in the rampage, was the son of an Italian mother from the northern city of Bologna and a Moroccan father who held passports from both countries, Italian media reported.

After a period living together in Morocco, his parents separated, and the mother, Valeria Collina, returned to Italy,the Italian newspaper Corriere della Sera reported.

At the time of the attack, Zaghba was working in a London restaurant and continued to have contacts with his mother in Italy, where he visited in 2016,

The terrorist — who was born in the Moroccan city of Fez in 1995 — had broken off relations with his father, Reuters reported, citing the Corriere della Sera.

According to The Guardian, Collina told L’Espresso magazine that her son phoned her Thursday, characterizing it as the “call of farewell.”

“Even though he did not say anything in particular, I felt it from his voice,” she said.

“We have always tried to control his friendships, but the Internet came around. Then in London he was with the wrong people. I understand why the imams don’t want to celebrate his funeral.”

During the call, Zaghba and his mom discussed her upcoming visit to London. She said that even after the London attack, she had no suspicions that her son was involved.

“I only found out later that [the other assailants] were his friends, and I told myself that maybe he’s hiding from the authorities to not get into trouble, since in Italy he was still being monitored,” she said.

British police did not immediately comment about the man Tuesday.

“We haven’t released anything at the moment, nor are we confirming anything but as soon as we are ready to name him, it will be on our Web site. We’re hoping to get that out soon,” a London police spokesman said.

The other two attackers were identified Monday as Pakistan-born Khuram Butt, 27, and Rachid Radouane, 30, both from Barking.

The three men were shot dead by police after killing seven people and wounding 48 others in the Saturday night rampage.

Redouane’s estranged wife Charisse O’Leary, 38, told a pal the killer wouldn’t let their daughter watch TV in case it “made her gay” and didn’t want her attending dance classes, The Sun reported.

“She hated him in the end. He was a horrible person,” one of O’Leary’s former co-workers told The Daily Mail. “She didn’t say what happened but it seemed to me like it was domestic violence.”

It also emerged that Butt got into a “violent scuffle” with a member of the anti-extremism organization the Quilliam Foundation.

The group said Butt accused one of their members, Dr. Usama Hasan, of being an apostate who took “government money to spy on Muslims,” and lunged at him twice when they got into a fight.

The Quilliam Foundation reported Butt to authorities, who said he was “already known to intelligence.”

Meanwhile, British Prime Minister Teresa May said she expects the UK’s intelligence service M15 will review how they dealt with the terrorists in the London Bridge attack.

“What the government needs to do, and what the government that comes in after Thursday’s election needs to be willing to do, is to give more powers to the police and security service when they need them, needs to deal with this issue of terrorism and extremism online and also needs to be able to call out extremism here in the United Kingdom,” she added.