The Seven Stages of an

Undercover Investigation. Worth reading. Two points to note:
First, there really are good guys in ATF, who care about the law and catching actual bad guys.
Second, along with bad general agents, there are a lot of bad/dumbass/treacherous people in the upper reaches:
The root of Dobyns’ problems may go back to the publication of a book about the Hells Angels, another recreational group of fun-loving motorcyclists known for their civic spirit. Sort of like the Boy Scouts on wheels. Angels of Death: Inside the Biker Gangs’ Crime Empire describes in some detail Dobyns’ infiltration of the Hell Angels, even becoming a full patch member, as part of ATF’s Operation Black Biscuit. I was told that the book’s description of undercover “sources and methods” gave ATF management a serious case of heartburn. It did not help that the federal prosecution basically fell apart when the case went to trial, with ATF management and federal prosecutors turning on each other as the mosquitoes dive-bombed their case.
That the good guys can repeatedly put their ass on the line, knowing the past history of the brass and prosecutors, is somewhat amazing. A good thing, but amazing.