Russian authorities are denying relatives of slain opposition leader Alexei Navalny access to his body for a third day after he died in prison in the Arctic Circle, his group said today, clarifying that the dissident’s mother was “not given permission” to enter the morgue where his body is kept.

“Alexei’s mother and her lawyers arrived at the morgue early this morning. They were not allowed to enter. One of the lawyers was literally pushed out. When they asked the staff if Alexei’s body is there, they did not answer,” Navalny’s representative Kira Jarmis wrote on social media.

Jarmis added that Russian investigators have not yet determined the cause of Navalny’s death and the investigation has been extended, as they told his mother and his lawyers.

The mother of the Russian dissident, Lyudmila Navalnaya, already arrived on Saturday at the penitentiary colony in the Arctic Circle, where her son was being held serving a 19-year sentence.

Navalny, 47, died on Friday after, according to Russian prison authorities, he “felt unwell” after a walk. Since then his body has been in the mortuary of Salekhard, the administrative capital of Yamal district.