Police in Argentina are continuing their investigation into Liam Payne's death ... conducting another round of raids on the homes of 2 hotel employees and a "friend" of the former One Direction singer, TMZ has learned.
Law enforcement sources in Buenos Aires tell TMZ ... officers conducted the raids Tuesday night, while also searching the hotel lockers of the workers and reviewing security footage from the hotel, CasaSur Palermo.
We're told cops believe the workers had contact with Liam before the entertainer plunged to his death from the balcony of his third-floor room into a courtyard on October 16.
Our sources say investigators identified Liam's "friend" with the help of text messages on his cell phone, which was examined by police to see who sold him drugs.
But, we're told, investigators did not find the "friend" at his home during Tuesday's raid.
You may recall ... in late October, police carried out the first wave of raids at CasaSur, seizing electronic and paper records and videos of the hotel's underground area, according to our sources.
Sources also told us initial autopsy results revealed Liam had "pink cocaine" in his system, a dangerous cocktail that typically combines meth, ecstasy and ketamine, as well as other narcotics.
Photos snapped inside Liam's room showed white powder scattered across a table with burnt tinfoil and other paraphernalia.
So far, police have not arrested or charged anyone in the case ... but it looks they're heading in that direction.