( CNN ) Workers digging underneath a Paris supermarket have made an unsettling discovery : as many as 200 skeletons . The grocery store , Monoprix , was doing some renovations in January and workers removing an underground wall discovered the bones . The area was apparently part of a cemetery for the Hospital of the Trinity , according to CNN affiliate , France 's BFM-TV . The cemetery operated from the 12th century to around the 17th century . Researchers and archeologists are conducting carbon dating and DNA testing to try to figure out when and why the people died , the affiliate said . It 's clear they all died around the same time , lead archeologist Isabelle Abadie told BFM-TV , because of the way the bodies were neatly arranged . `` What 's surprising is the bodies were not thrown in ( the graves ) but were carefully placed there in an organized manner . The individuals , men , women , and children , were placed head-to-toe , '' to fit as many as possible in the grave , Abadie explained . Paris suffered several plague epidemics during the times that the hospital was in operation , as well as a smallpox outbreak in the 17th century . Archeologists working the site have found eight common graves in an area that is 100 square meters , with seven of the graves containing between five and 20 skeletons each and another site with more than 150 skeletons , BFM-TV said . The groupings suggest that whole families were buried together . Abadie told BFM-TV that when the cemetery was shut down centuries ago , most of the remains were moved to the Catacombs of Paris . `` But apparently the job was not done well , '' she said . CNN 's Alanne Orjoux contributed to this report .
More than 200 skeletons found under Monoprix grocery store . The store is on a site where a hospital cemetery was located , dating to 12th century .