A court in the Russian city of Astrakhan has rejected a request for the early release of the son of leading Crimean Tatar politician Mustafa Dzhemilev.
Khaiser Dzhemilev was arrested in May 2013 by Ukrainian authorities in connection with the shooting death of a friend.
He has said that he shot his friend by accident.
After Russia's illegal annexation of Crimea in March 2014, authorities in Crimea's Russia-imposed government took over the case and transferred Dzhemilev to the Krasnodar region of southern Russia.
A Krasnodar court in June 2015 sentenced Dzhemilev to five years in jail on charges of theft, inflicting death by negligence, and possessing a firearm.
In September, Russia's Supreme Court reduced his prison term to 3 1/2 years.
His 72-year-old father, Mustafa Dzhemilev, is a Ukrainian lawmaker and a well-known Soviet-era human rights activist.
A former chairman of the Mejlis of Crimean Tatar people who strongly opposed Crimea's occupation and annexation by Russia, he is currently living in Kyiv.
He claims that Russia is holding his son hostage.