NBC News revealed late last week that former Russian political candidate and anti-corruption activist Alexei Navalny died in government custody.  

Navalny's death was announced on Friday by the prison service for the Yamalo-Nenets region, which was where Navalny was being held.

Supporters say activist was convicted of trumped up charges

"On February 16, 2024, in penal colony No. 3, convict A.A. Navalny felt unwell after a walk, almost immediately losing consciousness," the statement read.

"The facility’s medical workers immediately arrived at the scene and an emergency medical team was called in," the prison service insisted.

"All necessary resuscitation measures have been carried out, but they did not yield positive results. Emergency medics confirmed the death of the convict," it went on to add.

Navalny was serving a 30 ½-year prison sentence at an Arctic facility on fraud and extremism that supporters say were trumped up.

Navalny's widow says regime members "will be brought to justice"

For her part, Navalny's widow spoke to attendees at the Munich Security Conference and blamed her 47-year-old husband's death on Russian President Vladimir Putin.

"I don’t know whether I should believe the news," NBC News quoted her as saying. Mrs. Navalny added that she would like Putin and members of his regime "to know that they will be punished for what they have done with our country, with my family and with my husband. They will be brought to justice, and this day will come soon."

According to NBC News, Leonid Volkov was "a close ally" of Navalny who also served as a spokesperson for the political activist and he released a statement on Friday questioning official claims.

The Federal Penitentiary Service of Russia in the Yamalo-Nenets Autonomous Okrug is spreading the news of Alexey Navalny's death in IK-3. We have no confirmation of this yet. Alexey's lawyer is currently on his way to Kharp. As soon as we have some information, we will report on…

— Кира Ярмыш (@Kira_Yarmysh) February 16, 2024

"The Federal Penitentiary Service of Russia in the Yamalo-Nenets Autonomous Okrug is spreading the news of Alexey Navalny's death in IK-3," Volkov wrote on X, the social media platform previously known as Twitter.

Joe Biden: "Make no mistake, Putin is responsible"

"We have no confirmation of this yet. Alexey's lawyer is currently on his way to Kharp. As soon as we have some information, we will report on it," Volkov added.

NBC News noted that President Joe Biden spoke up as well, saying, "Make no mistake, Putin is responsible for Navalny's death."

While Biden did not provide any details, he said "there is no doubt that the death of Navalny was the consequence of something that Putin and his thugs did."