It does not matter whether or not they believed they hit the guy--they were supposed to make a complete report of ANY weapon discharge, let alone an entire magazine's worth. They didn't do so. The only report filed at the time, said that the guy absconded into Mexico, no mention of a gun, no mention that Ramos capped off an entire magazine at him.
I "police my brass" all the time.
Some free advice: do NOT do that if you are ever involved in a self-defense shooting. Don't touch a damn thing until the investigator(s) release the scene. Ramos and Compean knew that they weren't supposed to "police their brass" until the investigation team released the scene. The investigation team never showed up--because Ramos and Compean never reported the shooting in the first place. Ramos and Compean also knew that they were supposed to give a complete report of their weapon discharges--no matter if they were deliberate or negligent, whether they killed somebody or missed completely--within one hour of the event. They didn't say squat about it until the IG showed up, and then changed their story completely from what they said to their supervisor at the time.
Perhaps they reload their spent casings.
The Border Patrol reloading spent pistol brass? ANY police department reloading spent pistol brass? Nope. Uh-uh. Maybe the SWAT snipers save their cases for the armorer to hand-load, but even that's doubtful.
I find it fascinating that you take an illegal alien drug smuggler at his word that he didn't have a weapon.... Do you?
Well, should I take them at their (initial) word that there were no shots fired and that this guy didn't have a gun, or should I take them at their (later, after the stuff started hitting the fan) word that, well, yeah, he really did have a gun, and that's why they fired those shots that they never reported in the first place? Which story should I believe?
What law enforcement agency did you used to work for?