ISIS followed their Amaq news agency claim of Tuesday’s attack in Liège, Belgium, with another claim in their weekly newsletter giving gunman Benjamin Herman the nom de guerre Bakr al-Beljiki.

Herman, 31, had been serving time behind bars for theft and drug offenses when he was given a temporary release on Monday. Before he was due to report back to jail on Tuesday, he shot and killed policewomen Lucile Garcia, 53, and Soraya Belkacemi, 45. A man sitting in a nearby car, 22-year-old Cyril Vangriecken, was wounded in the attack.

Herman then took a custodial worker hostage at a school, where he reportedly asked if the employee was Muslim and observing Ramadan. When she replied yes to both questions, he said he wouldn’t harm her, and the woman tried to convince him to leave the schoolchildren alone. Herman was shot and killed by police; the custodian wasn’t injured.

The gunman was heard to have shouted “Allahu Akbar” at various points in the attack. The night before the attack he killed a former fellow inmate, Michael Wilmet, 30, by beating him to death with a hammer.

Interior Minister Jan Jambon said “there are signs he was radicalized in prison,” but authorities were questioning whether it was “that radicalization which drove him to commit these acts.” Herman reportedly had been granted temporary leave from prison multiple times before the attack and was scheduled for release in 2020.

In ISIS’ al-Naba newsletter, the terror group cited “private sources” as confirming Herman “has been a Muslim since his time in prison in Belgium.”

“It is noteworthy that the Crusader Belgium witnessed bloody operations and attacks of soldiers,” the ISIS article said, adding that the attack was “in response to their participation in the crusader alliance against the state Islamic countries.”

ISIS said Herman was “one of the soldiers of the Islamic State.”

Online, ISIS supporters seized on the attack to promote Herman and urge others to emulate his attack.

“Together we will stand up, once filled with iman, men who answered the call, terrorizing the world,” stated one poster, citing an ISIS song.

Another poster featured a photo of Herman and a quote from late ISIS spokesman Abu Muhammad al-Adnani promising “what is coming will be more wretched and more bitter.”

The most recent poster from ISIS supporters, featuring a selfie of Herman, stated, “We swear to break your necks and shed your blood everywhere else, this is the promise of Allah and we will make it come true. Beware. The coming will be the most terrible and bitter.”