Four people have been killed in the stabbing at the Paris police headquarters, according to CNN affiliate BFM TV.

Loïc Travers, a police union secretary, told BFM TV that five were dead, including the attacker.

The motive of the attacker, who was a longtime administrative employee for the police, is still unknown.

“He has been with us for over 20 years,” Travers said, speaking outside the police headquarters.