One of the first guys I met was an older (to me, I was 19 yo back then) guy in a cruising park in Ukraine, huge cock, later I found out he was a cop, our friendship lasted many years until I moved from there.
The second one was also in Ukraine, a cop who used to work as a guard in our dorms, married very good looking guy, his wife was pregnant and one night we got drunk with some other friends, that night he fucked me.
Third one was in Montreal, I met this hot muscle bear at the Eagle Noir, we went to his place, fucked all night. In the morning I saw his uniform hanging, he said: yeah I'm a cop.
Here in NYC I posted an add on craigslist, i didn't know he was a cop until he showed up, he still comes once in a while, very aggressive and dominant, he sits on my chair watching porn while I suck his thick cock. I posted a video of me sucking him off here.
That's pretty much it regarding cops, but if we talk about military men I have met lots while in the Army, in California near the DLI in Monterey, in DC and some from Fort Hamilton in NYC where in live now.