Or because he just didn't want to do the paperwork. The seemed to be a bit lax in following regulations there. There really wasn't any evidence they knew they had hit the suspect. They saw him climb into a car on the Mexican side that picked him up.
The suspect's testimony was also not very consistent, and parts of it weren't even close to believable.
Ramos assisted in the coverup and then lied in an official inquiry along with Compean in order to cover up the circumstances of what had occurred.
He didn't report discharging his weapon. I don't remember evidence of him covering up the incident beyond that, nor do I remember hearing that he lied during the inquiry.
I do kind of remember hearing that Compean's statements in the inquiry weren't perfectly consistent.
Neither the agents, nor the suspect ended up with much credibility. The suspect said he didn't have a gun or anything in his hand that could have been mistaken for a gun. Compean said he saw a gun, but the jury obviously didn't believe him because he had destroyed his own credibility. However, I really don't understand how they could have believed the suspect either, so I don't understand how the case was proved beyond a reasonable doubt.
Of course the suspect was also allowed to lie on the stand and make it sound like he had innocently gotten caught up in this one drug delivery because he desperately needed the money, but that the was an innocent, law abiding person other than that.
They already had evidence that he had taken in another load at the time of the trial, but the jury was not allowed to hear about that. At least he wasn't granted immunity for that other incident and was convicted. However, his sentence was only 57 months.
He removed physical evidence from the incident scene and he disturbed the incident scene as well - knowing full well that if he filed a written incident report as the law required or if came to light in any other way, there would be a routine physical inspection of the scene that he deliberately had interfered with.