and it's not a bullet she finds, but a shell casing. a ballistics expert testified that casing matches five others found at the murder scene. they were fired from the same, unknown weapon, capable of chambering 45 auto caliber aj in addition. >> did you have an in addition as to the type of weapon that was? >> it's consistent with having been fired from a glock. >> a glock, that's the type of gun an employee says hernandez is carrying when he returns home minutes after the murder. >> in my opinion, the firearm showed in the video stills have a glock pistol. >> the murder weapon, one prosecutors say is in hernandez's hands that night, has never been found. they suspect it's in a box inside this bag. that's shayanna jenkins -- hernandez's fiancee.