Crime Scene Scenario – Mistakes or No Mistakes?

Criminalist Ben Baldazana is collecting evidence from the scene of a shooting. After locating the revolver suspected of firing the shots, Ben picks the gun up by the grip, unloads it, and places the ammunition in an envelope. He then attaches an identification tag to the grip. Searching the scene, Ben finds a bullet lodged in the wall. He uses pliers to grab the bullet and pull it from the wall, then inscribes the bullet with his initials and places it in an envelope. What mistakes, if any, did Ben make in collecting this evidence?