Media reports in Crimea say the body of one of two missing Crimean Tatars was found in the annexed region's capital, Simferopol, on October 14.
Reports cite the Kryminform website as reporting that Belyal Belyalov, who was university student, died after smoking an unspecified substance.
According to the Moscow-backed Kryminform, the second missing young Crimean Tatar, Artyom Dayrabekov, who also reportedly smoked the substance, was saved by doctors.
Dayrabekov's relatives, who had reported the two young men's disappearance, refused to comment on Kryminform's report.
Crimea's pro-Russia Interior Ministry also refused to comment on the situation.
Crimean Tatar Edem Asanov, 25, was also found dead last week after being reported missing.
Most Crimean Tatars -- a Turkic-speaking Muslim minority native to Crimea -- opposed Russia's annexation of the peninsula.