KYIV -- Ukraine's foreign minister has called the killing of an activist attorney in Kyiv "a challenge to the state" as the authorities, facing public outrage, opened a murder investigation into the death of Iryna Nozdrovska.
The Kyiv regional prosecutor's office and the National Police executive said on January 2 that they are closely monitoring the investigation into what they called a “murder" the day after Nozdrovska’s body was found floating in a river in Kyiv's Vyshhorod district.
The lawyer was reported missing on December 29 after she helped to make sure the man convicted of causing the death of her sister was not released from prison, in a high-profile case that was seen a test of the Ukrainian justice system's ability to fairly prosecute people with links to people in power.
Foreign Minister Pavlo Klimkin underscored the national significance of Nozdrovska's death on January 2, calling it "a challenge to the state."
This is "a test of our society's ability to protect female activists and to ensure justice as a whole," Klimkin said in comments on Twitter on January 2 that came as the U.S. Embassy in Kyiv expressed "shock" over the killing and hundreds of people rallied in Kyiv demanding a thorough investigation.
In a blunt message on Twitter, the U.S. Embassy in Kyiv said it was "shocked and saddened by the death of activist Iryna #Nozdrovska" and said that "those responsible must be brought to justice."
The demonstrators in Kyiv on January 2 demanded that the murder investigation be conducted by Kyiv city investigators, saying they did not trust regional law enforcement officers. They also demanded the resignation of Interior Minister Arsen Avakov.
WATCH: Protesters gathered in Kyiv to demand justice for a lawyer whose body was found on New Year's Day. (RFE/RL's Ukrainian Service)
Regional police chief Dmytro Tsenov met with the protesters in front of the building of the Kyiv regional police headquarters, and told them that a special team of experts was set up to investigate Nozdrovska's death.
Nozdrovska was the target of threats for her efforts in the case of Dmytro Rossoshanskyy, who was convicted of causing the death of Nozdrovska's sister, Svitlana Sapatinska, in 2015 when he hit her while driving his car.
Judges rejected an appeal by Rossoshanskyy, the nephew of a Kyiv region judge, to overturn under an amnesty his seven-year prison term on December 27, thanks in large part to efforts by Nozdrovska to raise public awareness about the case.
Nozdrovska and others mentioned that the young man's "drug-addict mates" had come to the court to take him home ahead of his expected release. She thanked the judges for what she called "one of the extremely rare just court rulings."
Ukrainian lawmaker Mustafa Nayyem wrote on Facebook on January 1 that Rossoshanskyy's father had threatened Nozdrovska at the December 27 hearing. According to Nayyem, the threat was "You will end up badly."
AFP reported that the Kharkiv Human Rights Protection Group in a statement said Nozdrovska had received threats during the trial "from Rossoshanskyy himself, and from his mates."
In Ukraine, relatives of officials often either get away with crimes or manage to get released earlier due to corruption, which observers say harms the country's everyday life and economy and hurts Ukraine's chances of throwing off the influence of Russia.
Moscow illegally annexed Ukraine's Crimean Peninsula in 2014 and backs separatists whose war against government forces has killed more than 10,300 people in eastern Ukraine since April 2014.