Liam Payne was likely under the influence of potent hallucinogenic drugs when he died in Argentina last Wednesday.
Buenos Aires police officers told TMZ their operating theory is that the former One Direction star was potentially high on an illegal drug known in Argentina as cristal - a dangerous substance that "causes users to experience extreme highs and extreme lows, often making them aggressive".
The substance is also known to cause psychotic attacks and hallucinations.
Police told the outlet that Payne's reportedly erratic behaviour may be partly due to the drug, and may have caused him to hallucinate, leading him to fall from the third-storey balcony of his hotel room at CasaSur Palermo Hotel in Buenos Aires.
On Friday, Page Six reported that the star was struggling with substance abuse when he died at age 31, noting that he was "battling a very significant drug addiction and his treatment, as those who knew him will attest, was not working".
Photos of Payne's destroyed hotel room were released after his death. The images showed what appeared to be a wooden dresser covered in burn marks, white powder, pieces of tin foil and a burnt tea light candle.
Although police have said Payne's behaviour was consistent with that of cristal users, they are still waiting for test results on the narcotics and medications recovered from the scene.