Oct. 14 (UPI) -- Authorities said Monday they have arrested five people -- including an imam from a French mosque -- in the knife attack that killed four law enforcement employees in Paris this month.
Officials say Michael Harpon stabbed five people at the police headquarters building in Paris on Oct. 3 before he was shot dead by officers. Four died and a fifth was seriously hurt.
Investigators say Harpon converted to Islam about 10 years ago and was in contact with supporters of Salafism, an ultra-conservative branch of Sunni Islam.
The arrested imam, who is listed by French authorities as a potential security risk, is an Islamic leader at a mosque in Gonesse that Harpon often attended, authorities said. The mayor of Gonesse said he'd been dismissed by his Muslim association employer.
French Interior Minister Christophe Castaner is under pressure to explain how a police employee was allowed to become radicalized, and why it wasn't detected.
Four others linked to the attack have also been arrested.