PARIS (AP) — France's interior minister acknowledges there were "malfunctions" that failed to prevent a deadly attack inside Paris police headquarters by a police employee.

Christophe Castaner said Sunday the attacker was a "well-rated" police employee and had "no indication of radicalization" in his internal police file. The attacker was killed after stabbing four people to death.

The Paris prosecutor says the attacker was likely in contact with members of an ultra-conservative Islamic movement.

Speaking on TF1 television, Castaner said "clearly there were malfunctions," without elaborating. He said the attacker had an "altercation" with colleagues earlier about the deadly 2015 Islamic extremist attack on satirical newspaper Charlie Hebdo, but his colleagues didn't press for any action against him.

Castaner also dismissed calls for his resignation over the slayings.