Are pictured in Nice, southern France, Saturday Nov. 7, 2020, during a ceremony in homage to the three victims of an attack at Notre-Dame de Nice Basilica on October 29, 2020.
The prosecutors' office said one of the photos showed Abdoullakh Anzorov, the Chechen refugee identified as the killer of teacher Samuel Paty.
But investigators have as yet been unable to interview the suspected church attacker, previously identified as Ibrahim Issaoui, because he remains in serious condition in a Paris-region hospital, the prosecutors' office said a statement.
The prosecutors' office said it opened a formal investigation Friday on terrorism charges that will enable investigators to keep probing whether the suspected attacker had any accomplices in France, Tunisia or Italy.
He traveled through Italy before reaching Nice less than 48 hours before the attack in the Mediterranean city's Notre Dame Basilica.