Police officer saw aircraft flying over current office of satirical newspaper . Later seen hovering over area where jihadist killed four at Jewish store . Police also investigating a dozen sightings across the capital on Tuesday . Comment:
Police officer saw aircraft flying over current office of satirical newspaper . Later seen hovering over area where jihadist killed four at Jewish store . Police also investigating a dozen sightings across the capital on Tuesday . France on high alert after terror attacks that killed 17 people in January .