The judge's son, Abubakar Yangulbayev, who is a lawyer for the Committee Against Torture, told Current Time on January 24 that his father and sister left the country fearing for their safety after the authoritarian ruler of the North Caucasus region of Chechnya, Ramzan Kadyrov, publicly threatened to "eliminate" the family.

The 52-year-old Zarema Yangulbayeva, aka Musayeva, was taken from her apartment in Nizhny Novgorod on the evening of January 20 by masked men who introduced themselves as Chechen police officers.

On January 21, Kadyrov said Yangulbayeva faces a "real prison sentence for attacking a law enforcement officer" and that Chechen authorities "will take care of" her son, while her entire family could find themselves "either in jail or underground."

In a separate statement, Kadyrov called the Yangulbayev family, Igor Kalyapin, the chairman of the Committee Against Torture, and journalist Yelena Milashina, who often writes about rights abuses in Chechnya, "terrorists."

Amnesty International described Yangulbayeva's detention as "kidnapping" and urged Russia's federal authorities to act on the "lawlessness" that has "spilled out" of Russia's North Caucasus region.

Abubakar Yangulbayev told RFE/RL that his mother's lawyer has been unable to visit her and was not allowed to be present at a court hearing in Chechnya that decided on her pretrial arrest.

"We do not know where exactly she is now, on what grounds she was detained.... What is more important is the situation around the accusation about her allegedly attacking [a police officer]. According to what [the Chechen authorities] say, that incident most likely happened during detainment or while she was transported to Chechnya.

"In that case, it is illegal, as what they claim happened in a different judicial territory and Chechen authorities cannot prosecute her on that charge," Abubakar Yangulbayev said.

Yangulbayev, who is currently out of Russia, added that two houses in Chechnya that are home to 15 of his relatives are currently empty, suggesting that his relatives may be being held in custody.

He added that he has confirmed information that his three uncles are currently in police custody in the Chechen town of Urus-Martan.

"When [the relatives] were detained, police took their passports and property ownership documents. Some of my relatives were beaten. Police put plastic bags over the heads of almost all of them," Abubakar Yangulbayev said.

Kremlin spokesman Dmitry Peskov said on January 21 that the Kremlin is not aware of the situation around Zarema Yangulbayeva, emphasizing that she is the wife of a federal judge.

"The Kremlin has no details about the abduction of a federal judge's wife in Nizhny Novgorod and prefers not to believe in it," Peskov said at the time.

Abubakar told Current Time that Chechen authorities began their pressure campaign on his family in 2015.

Yangulbayev says his mother and father have been residing outside of Chechnya for many years and have nothing to do with any developments in Chechnya.

In late December, authorities detained dozens of relatives of Chechen bloggers who reside abroad and often criticize Kadyrov. Most of them were later released, but some remain in custody.

Russian and international human rights groups have for years accused Kadyrov of overseeing grave human rights abuses, including abductions, torture, extrajudicial killings, and the persecution of the LGBT community.

Kremlin critics say Putin has turned a blind eye to the abuses and violations carried out by Kadyrov because he relies on the former rebel commander to control separatist sentiment and violence in Chechnya.

Chechnya went through two devastating post-Soviet wars and an Islamist insurgency that spread to other mostly Muslim regions in the North Caucasus.