A judicial official says French authorities are questioning 12 suspects in connection with an alleged radical Islamic cell believed to have been behind the firebombing of a Jewish grocery north of Paris last month.

Paris prosecutor's office spokeswoman Agnes Thibault-Lecuivre says the suspects were held Monday after raids in Strasbourg, Cannes and the Paris area. Earlier, authorities had said 11 were being questioned.

Police in Strasbourg shot dead suspect Jeremie Louis-Sidney after he opened fire with a revolver Saturday. The 33-year-old was the alleged leader of a cell behind a Sept. 19 grenade attack on a kosher grocery in Sarcelles.

Under French anti-terrorism law, the suspects can be held for up to 96 hours before facing preliminary charges or being released — or no later than Wednesday in this case.