It's an epistomelogical challenge alright, Ms. Taylor. Note that people who claim to be closest to law enforcement—ex-cops, relatives, attorneys, etc—accept Cab's account as genuine. In fact, Cab's harshest critict, Steve Rodgers, who claims to be active duty LEO, calls him a "coward" & suggests he worked in some puny, non-account agency, but never seems to doubt that Cab was a cop.
Of course, all of these people could be liars or poseurs. Who knows?
But, going back to the days of Usenet newsgroups, there was alt.law-enforcement, where cops, civilians, supporters & critics all gathered to discuss. If you showed up on the group claiming to be an active duty LEO you'd receive behind-the-scenes e-mails from other, established cop users inviting you to sign on to one of the many Internet bulletin boards intended for cops only, where verification was necessary as a perquisite for membership. If you didn't sign up, no problem. As long as you towed the company line. Let someone make the claims Cab has, & I guarantee you every single critique from the LE side would call him a liar, insist he never was a cop. That no one with knowledge of or experience in law enforcement seems to have done so here is telling.