No one that does their job and enforces the law should be convicted solely on the statements of a foreign national drug runner.
I'm confused that you are confused. If you don't know what exactly they covered-up, then how do you know they were convicted "solely" on the statements of the drug-runner?
That’s what I’ve read, heard, and seen. If you have articles about this I’d be happy to see them. I read that they were sloppy after words and that supervisors heard the shots so there wasn’t a need to file a report (that was my understanding anyway).