Paris (CNN) -- French police traded gunfire Saturday in a Strasbourg apartment building with the top suspect in a September supermarket bombing, leaving the 33-year-old man dead and one police officer wounded, prosecutors said.
The incident was part of a far-reaching, coordinated counterterrorism operation targeting radical Islamists that led to 10 arrests, Paris prosecutor Francois Molins told reporters.
A chief focus of Saturday's sweep was Jeremy Sidney, a 33-year-old former convict who at one point "converted to radical Islam," Molins said. The prosecutor said Sidney's DNA was found on a small explosive device thrown September 19 into a kosher supermarket in Sarcelles, outside Paris, wounding one customer.
Police officers went Saturday morning to an apartment building in Strasbourg, in eastern France, that was home to one of Sidney's two "religious wives," said Molins. According to preliminary reports, Sidney shot at police as soon as they opened the door -- firing six shots and emptying his .357 Magnum revolver before being killed in an exchange of gunfire.
A police officer who was shot in the thorax is expected to survive, said Molins. He credits the officers' bulletproof vests and helmets with preventing more injuries.
Inside the man's apartment, police found a female companion with a 6-year-old child and a 1-month-old infant, according to Strasbourg prosecutor Patrick Poirret.
The woman was taken into custody as part of the terrorism case, Poirret said. Child welfare workers took custody of the 6-year-old, but the infant was allowed to remain with the woman because she is breastfeeding, Poirret said.
Sidney -- who was born in Melun, France -- was sentenced to two years in prison in 2008 after being convicted of drug trafficking, said Molins. French intelligence operatives had been monitoring him since spring -- well before the Sarcelles' attack -- but he had not been questioned by authorities.
"He appeared (to be) a delinquent converted to radical Islam," said Molins, who later added that Sidney never trained to fight abroad.
A total of 10 people were arrested Saturday across France, as part of the law enforcement operation. One man who was arrested on top of a building in Torcy, about 25 kilometers (16 miles) east of Paris, was armed with a loaded. 22 caliber pistol, Molins said.
Authorities can detain the suspects for 96 hours from Saturday morning, at which time they must press charges or release them.
All 10 people are being held on suspicion of having links to terrorism, manufacturing deadly explosives, illegal possession of weapons and attempted homicide of police officers. Three of them have criminal records for drug trafficking, theft or violence, according to Molins.
"They are common criminals who started to be radicalized to become radical Islamists and jihadists," he said.
Police seized a number of items such as ammunition, a list of "Israelite" organizations in and around Paris, a publication produced by al Qaeda in the Arabian Peninsula, wills, computer equipment and 27,000 euros ($35,000) in cash, the prosecutor added.
Saturday's operation targeted members of what Molins called an organized terrorist cell.
"We are dealing with a group of a few people who are in constant contact and are supporting each other on a regular basis," he said.
French Interior Minister Manuel Valls briefed President Francois Hollande on the operation Saturday.
Hollande reiterated his country's determination to protect the French people against all forms of terrorist threats.
He praised the action of police and asked Valls to take necessary measures to maintain vigilance, Hollande's office said.
CNN's Pierre Meilhan and Laura Smith-Spark contributed to this report.