An IT worker who killed four people at Paris police headquarters with a knife last week had a USB drive with personal details about his colleagues, French daily Le Parisien reported on Monday.
The attacker on Thursday killed three police officers and an administrative worker before being shot dead by police. Initial investigations have revealed that the Martinique-born man, a convert to Islam, had had contacts with individuals who are likely to belong to an Islamist Salafist movement.
Le Parisien reported on its website that a USB memory device found in the assailant's house had personal details about several dozen of his colleagues at police headquarters, as well as several Islamic State propaganda videos.
The paper added that it was not clear whether the attacker had shared that information with others.
Authorities fear that police officers' lives could be at risk if details about their identities or addresses fall in the wrong hands.
Police sources could not immediately comment on the paper's report.
French Prime Minister Edouard Philippe told a weekly on Sunday that he had ordered inspectors to review procedures in the intelligence department of the police headquarters and anti-terror intelligence unit to detect signs of radicalization among civil servants.