Bakhtovar Jumaev, a Moscow-based Tajik lawyer, says officials in Tajikistan have opened a case against him for inciting "extremist activity."
Jumaev told RFE/RL on June 25 that the Panjakent Organized Crime Department summoned his father a day earlier to inform him that they had opened the proceedings.
"I told him that my son was neither an extremist nor a terrorist, and that the accusations against him were slanderous," Jumaev's father said.
The Panjakent police department did not respond to calls from RFE/RL for comment.
Jumaev said earlier this month that officials told his family they should demand his return to Tajikistan.
After the warning, Jumaev left Russia for a third country. Without disclosing details, Jumaev said he had received information that Russian officials were planning to detain and deport him to Tajikistan.
Several Tajik activists in Russia say their relatives in Tajikistan are being targeted by the government in an effort to silence and threaten its critics abroad.
At least 15 Tajik activists have disappeared in Russia since 2015, human rights activists say. Some of them have reappeared in Tajikistan -- often in jails, facing dubious charges ranging from fraud to extremism. The whereabouts of others remain unknown.
Jumaev is a colleague of Izzat Amon, the head of the Center for Tajiks in Moscow, who was charged with fraud after his forced return to Dushanbe from Moscow in March.
Amon faces up to 12 years in prison if found guilty. His supporters dismiss the charges as politically motivated.
Amon's nonprofit organization in Moscow has helped Tajik migrant workers find jobs, obtain work and residency permits, and get legal advice.