The Drug Enforcement Administration is tasked, naturally, with fighting the drug war. But because the cartels are so powerful and international, the DEA's tactics often wind-up more like the CIA than the FBI. Long-term Deep Cover Agents, Black Helicopters, the whole nine. Because CIA Evil, FBI Good, this already tends to push them towards the Dirty Cop end of the spectrum.
Then because drugs are such a profitable business, the people they end up infiltrating are usually buried to their ears in Hookers and Blow. So why not get a piece of the action yourself? After all, Damn, It Feels Good to Be a Gangster!.
Therefore, almost any time a DEA Agent appears in a work, the chance of a FaceHeel Turn is immense, assuming they were ever a Face to begin with.
- One arc of Largo Winch sees Largo pursued by a zealous DEA agent convinced that he's using his corporate empire to run a drug-smuggling operation. He is, of course, in on it (the actual Corrupt Corporate Executive is the director of the airlines division, using jetliners to transport vast amounts of cocaine across the Atlantic. Largo blows up the plane with him, the DEA guy, the corrupt crew and the drugs on it as the least-messy resolution to the whole story).
- Gary Busey in Drop Zone intends to steal all his former colleagues' names and undercover assignments in order to sell them to a drug lord.
- James Munroe in The Expendables wants to usurp a Banana Republic and turn it into a narco-state.
- Léon: The Professional has Gary Oldman as Ax-Crazy DEA Agent Norman Stansfield. His whole DEA "crew" are all dirty cops.
- Licence to Kill has Killifer, the DEA agent in charge of helping Felix Leiter and James Bond arrest Big Bad druglord Sanchez, who accepts a bribe of two million dollars to help him escape custody and get the name of the agents that arrested him so he can kill them in revenge, which sets up the whole plot. Bond eventually feeds Killifer to the same bunch of sharks Leiter's leg was fed to.
- Witness: The murder of the undercover cop witnessed by Amish boy Samuel turns out to have been perpetrated by corrupt narcotics agents who are determined to keep the 22 million dollars they made from a drug deal a secret. The Police Chief is also in on this.
- Downplayed in Breaking Bad. While the DEA overall is given a very positive portrayal, Hank is a bit of a Cowboy Cop who isn't averse to underhanded or illegal methods to catch suspects. Especially once he realizes that his brother in law Walt is the real Heisenberg. The level of this betrayal wounds Hank so deeply that he goes off the deep end in his attempt to bust Walt, to such a degree that Hank single-handedly ruins any chances of making Walt pay for his crimes if the case ever actually went to court.
- At the end of Graceland's second season, Paige Arkin, the house's resident DEA agent, betrays Mike in revenge for his allowing a prostitute to die as part of an op.
- In Snowfall, DEA Agent Lorena is so obsessed with bringing down the Villanueva cartel that she tries to sabotage a CIA operation and nearly starts an ugly gang war. This eventually bites her in the ass when she bullies her way into Teddy's CIA operation; Teddy's partner El Oso was one of her favorite targets for harassment, and when he sees her in one of his warehouses, he panics and shoots her dead.
- In Proven Innocent, Davon Watkins' murder case involves a crooked former DEA agent who now works for a crime boss.
- Double Subverted in the Blindspot episode "Heave Fiery Knot", which sees the team chasing Valentine Barker, a supposedly corrupt DEA field agent who is using a DEA gun waltzing program (where agents go undercover and pose as weapons merchants using confiscated weaponry in an attempt to arrest the buyers) as a cover for selling guns to the Juarez Cartel. However, it turns out Valentine was framed, and it's her boss, Robert Kingston, the deputy director of the DEA, who is the arms dealer. He attempts to murder Valentine and is planning to ship Stinger missiles to the cartel.
- An episode of CSI: Miami has money (evidence of a crime) disappear from the lab, prompting a corruption investigation. The culprit turns out to be an Internal Affairs agent who'd become convinced the lab was corrupt, and decided to fake a crime to prove it.
- Subverted in Queen of the South, where the DEA agents are genuinely trying to stop drug trafficking in the US, but are stymied by corrupt CIA operatives.
- The resident DEA operative Eddie Guerra from Call of Juarez: The Cartel is a gambler and quite obviously shady. That said, the game eventually presents the resident FBI agent in equally negative light, contrary to the usual portrayal of that agency.
- Averted by Ricky Sandoval in Ghost Recon Wildlands, who spent seven years infiltrating the Santa Blanca Cartel and never went dirty (well, no more so than an undercover agent would be expected to while passing himself off as a ruthless drug dealer). Then it's revealed towards the end that it was Ricky who arranged the bombing of the American embassy in La Paz, deciding that the American government simply couldn't be relied on to act without "incentive". Whether or not this makes him corrupt or even a traitor, is largely up to the player.
- In "El Matador" after beating the La Valadora kingpin Helmut Koch the remnants of the cartel load all their valuables on a cargo ship to regroup elsewhere, when the player character attacks the harbor along with the DEA and the Private Military Contractors the police chief called in it turns out it's a Xanatos Gambit by the police chief to take over the cartel by having the paramilitaries and corrupt cops ambush the honest ones wiping out them and the La Valadora remnants to seize the cargo ship with the valuables.