Matthew Perry Death Investigators 'Confident' They'll Nail Suspect(s)

The feds probing Matthew Perry's death are "confident" they have the goods to take down the people who helped him obtain the ketamine that contributed to his death ... TMZ has learned.

DEA agents launched their Perry death investigation after the L.A. County Medical Examiner determined the "Friends" star died from drowning in his hot tub after taking ketamine, a dissociative anesthetic that has some hallucinogenic effects.

Our sources tell us ... the feds are aiming to charge the suspects with drug distribution resulting in death or great bodily injury, which carries a mandatory minimum of 20 years in prison.

We're told DEA agents are not just probing dealers ... they could also go after doctors if they wrote prescriptions "deemed outside the scope of medical necessity."

Further, the investigation has dug deep into the Hollywood drug scene. A search warrant was executed on Brooke Mueller, Charlie Sheen's ex-wife, as part of the probe ... and our sources confirmed that.

We reported Brooke's battles with addiction over the years, but it's unclear what, if any, connection she has to Matthew's case. We reached out to her attorney, but have not heard back.

And, there's this ... the DEA team investigating the Perry case only focuses on cases with the "resulting in death" charge, and we're told it's the same agents who helped nail the suspects in Mac Miller's fatal drug overdose.