(JTA) — A French justice official said his office will indict four men who are accused of aiding a terrorist to kill four people at a kosher supermarket near Paris.

Three of the men charged, all in their 20s, purchased materials for the killer, Amedy Coulibaly, Paris Prosecutor François Molins said during a news conference Wednesday. Another drove a vehicle for Coulibaly.

“They were part of a criminal terrorist organization,” Molins said of the men, who are in police custody. One of the accused is charged with supplying an automatic weapon to Coulibaly, who died on Jan. 9 when police stormed into the Hyper Cacher supermarket where he was holding 19 hostages for several hours. He killed four people, all Jews, during the first hour of the siege.

Coulibaly, who on Jan. 8 killed a police officer south of Paris, planned his attack together with Cherif and Said Kouachi, two brothers who killed 12 people at the offices the Charlie Hebdo weekly, which published many caricatures lampooning Islam. They were killed in a separate police raid near Paris on Jan. 9. In total, the three murdered 17 people.

The three killers are believed to have been part of the same terror cell, which according to French authorities was recruiting jihadists to fight in Syria. Police are looking for a fourth accomplice who may have participated in the actual attacks and is not among the four men in custody, according to Jean-Michel Decugis, police correspondent for the i-Tele network.

“They were in charge of logistics, one provided a car, the other a weapon,” Decugis said. At least one of the suspects confirms he aided Coulibaly but all are denying that they knew he intended to commit a terrorist attack, Decugis added.

A total of 12 people were arrested last week on suspicion of helping the Kouachis and Coulibaly, according to the French newspaper Le Figaro.