French authorities put a man under formal investigation Saturday, saying they suspected the 31-year-old of supporting Toulouse gunman Mohammed Merah, who killed a rabbi and three children outside a Jewish school last year.
The man is thought to have helped Merah plan the shooting spree, providing him with weapons and a bullet proof vest, a judicial source said, according to a Reuters report.
On March 19, 2012, Merah, a 23-year-old jihadist fanatic who claimed links to al-Qaeda, gunned down Rabbi Jonathan Sandler, 30, along with his two young sons, Aryeh and Gavriel. He also killed Miriam Monsonego, the 8-year-old daughter of Yaacov Monsonego, director of the Ozar HaTorah school, which has since changed its name to Ohr HaTorah.
Merah also killed three paratroopers in two separate shooting attacks in the week before he targeted the school.
He was gunned down in a shootout with French police two days after the incident. French media sources said at the time that he spent time training on the Afghanistan-Pakistan border, where he adopted extremist ideology.
The judicial source said the man was being probed on suspicion of involvement in a terror ring, as well as passing weapons and being an accomplice to the killings.
A formal investigation means police have serious evidence that the man was involved.
On Tuesday, French police arrested six people in connection with the attacks, four in Toulouse and two in Paris.
Most of the people arrested were related by marriage to Merah, and police hoped they could help shed light on where the killer received the money to purchase his firearms.
In the months since the attacks, French authorities have arrested and released several people and questioned dozens in connection with the shootings.