Paris ( CNN ) -- Police who searched buildings in Paris as part of a far-reaching investigation into a suspected terrorist cell found `` all the elements needed for making explosives , '' prosecutors said Wednesday . The searches were connected to a big police operation Saturday targeting radical Islamists suspected of involvement with the bombing of a Jewish supermarket in September . Paris prosecutor Francois Molins said Wednesday that the 12 suspects in custody would be detained for an additional 24 hours . Normally French authorities can only hold suspects for 96 hours before they must press charges or release them . Police who searched premises in Torcy , about 25 kilometers ( 16 miles ) east of Paris , overnight Tuesday found bags of potassium nitrate , sulfur , saltpeter , pressure cookers and headlight bulbs , all items useful in making homemade explosives , Molins said in a statement . A shotgun and handgun were also found , he said . The search continued Wednesday morning . The premises where the alleged explosives components were found are used by the same person at whose address a list of Jewish organizations was found by police Saturday , Molins said . Read more : Two arrested at London airport in terror probe . However , police inquiries suggest that two people suspected of throwing a grenade through the window of the Jewish supermarket in Sarcelles , a Paris suburb , may still be at large , he said . Given the nature of the discoveries made by police and the need to find all the members of the presumed terror cell , it was vital to extend the detention of the suspects by an additional 24 hours , Molins said . This step is allowed under French law if there is a serious risk of an imminent terrorist threat , and can be renewed once , leading to a maximum possible period of detention without charge of six days . It is only the second time this provision has been used since it came into law in 2006 , he said . `` We are clearly and objectively facing a terrorist cell of an extreme dangerousness , '' Molins said . Authorities will do everything in their power to put an end to the cell 's actions and avoid any risk of a terrorist attack in France , he said . The suspects are being held on suspicion of having links to terrorism , manufacturing deadly explosives , illegal possession of weapons and attempted homicide of police officers . Read more : Spain 'al Qaeda cell ' may have targeted Gilbraltar . Three of them have criminal records for drug trafficking , theft or violence , Molins told reporters Saturday . One man who was arrested on top of a building in Torcy on Saturday was armed with a loaded .22-caliber pistol , Molins said . The chief suspect in the September bombing , 33-year-old Jeremie Louis-Sidney , died in Saturday 's operation as he traded gunfire with police in a Strasbourg apartment building . French intelligence operatives had been monitoring him since spring -- well before the Sarcelles attack -- but he had not been questioned by authorities , Molins said . He was sentenced to two years in prison in 2008 after being convicted of drug trafficking . `` He appeared ( to be ) a delinquent converted to radical Islam , '' Molins said . Police seized 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 .
Bomb-making materials were found at premises used by a terror suspect , prosecutor says . `` We are clearly ... facing a terrorist cell of an extreme dangerousness , '' he says . 12 people held in connection with the inquiry are being detained for an extra 24 hours . Comment: