Iryna Farion, a former Ukrainian nationalist politician known for speaking out in defense of the Ukrainian language and against the use of Russian, has been shot dead in Lviv, Interior Minister Ihor Klymenko announced in the early hours of Saturday.
Farion was shot in the head outside her home on Friday evening by an unknown gunman. She later died from her injuries at a local hospital.
What do we know about the attack?
Klymenko said that authorities were examining multiple theories to explain the killing.
"The main theories currently under consideration are personal animosity, social and political activities of Ms Farion. We do not rule out the possibility that it was a contract killing," Klymenko wrote on the Telegram messaging service.
Lviv Regional Governor Maksym Kozytskyi said that Farion had died after being taken to hospital.
Ukrainian President Volodymyr Zelenskyy condemned the killing and ordered Klymenko and Security Service chief Vasyl Maliuk to solve the crime.
He said that all lines of inquiry were being investigated, "including one leading to Russia."
The Svoboda party, of which Farion was a member, blamed Moscow for the death in a statement without providing evidence.
Margarita Simonyan, editor-in-chief of Russian state broadcaster RT, celebrated the killing but did not claim Moscow was responsible for it.
"Iryna Farion, who dreamed of the 'complete elimination' of the Russian-speaking population, has been eliminated," Simonyan said in a post on Telegram.
Russian President Vladimir Putin cited the defense of Ukraine's Russian-speaking and ethnic Russian population as one of Moscow's war aims when he launched the invasion of Ukraine in February 2022.
Who was Ukrainian linguist Iryna Farion?
Farion served as a deputy for the far-right Svoboda party in Ukraine's parliament, known as the Verkhovna Rada, from 2012 to 2014.
She was known for statements in defense of the Ukrainian language and criticizing the widespread use of Russian in Ukrainian society, including by officials and soldiers.
Ukrainian is the country's only official language but substantial sections of the population, especially in Ukraine's south and east, speak Russian as their primary language.
Farion was herself from the western Ukrainian city of Lviv, which is predominantly Ukrainian-speaking.
Following student protests, she temporarily lost her position as a Ukrainian language professor at the University of Lviv, but was reinstated following a court ruling.
She had criticized the fact that members of Ukraine's Azov regiment continued speaking their mother tongue, Russian.
The ultranationalist Azov militia was integrated into the Ukrainian military in 2014 and was a major force in the defense of the city of Mariupol in the eastern Donetsk region. The city was captured by Russian troops in May 2022 following a siege lasting nearly three months.