The leader of the notorious Tsapok Gang, blamed for killings, robberies, and extortion in Russia's Krasnodar Krai, has been found dead.
Russia's Investigative Committee says Sergei Tsapok was found on July 7 in the infirmary of the detention center in Krasnodar where he was being held.
Detention center officials say Tsapok may have died of a stroke.
Tsapok's death was reported three days after a member of his gang, Igor Chernykh, reportedly committed suicide in the same detention center on July 4.
The two, along with Vladimir Alekseyev, were sentenced to life in prison in November for a series of murders, including the brutal slayings of 12 people in 2010.
The case of the Tsapok Gang sparked controversy after investigations revealed the group's ties to local Russian officials.
At his trial in November, Tsapok raised the possibility that he may be killed while in custody.