Alexei Navalny’s lawyer was briefly detained in Moscow on Tuesday after helping the opposition activist’s mother recover her son’s body.
Vasily Dubkov later told independent news outlet Verstka that he had been released, but did not comment on the reason for his detention.
However, he added that it was an obstruction of his activity as a lawyer.
Mr Navalny, Russia’s best-known opposition politician, died earlier this month in an Arctic penal colony while serving a 19-year sentence on charges widely seen as politically motivated.
The 47-year-old was a leading critic of the Kremlin and Putin’s regime.
With Mr Dubkov’s help, Navalny’s mother Lyudmila succeeded in obtaining the release of her son’s body last Saturday, eight days after his death.
She had earlier accused investigators of trying to “blackmail” her by withholding the body unless she agreed to bury it without a public funeral, which she refused to accept.
President Vladimir Putin’s spokesperson claimed that the Kremlin has no involvement in the arrangements for Mr Navalny.
Navalny’s spokeswoman said earlier on Tuesday that his team had so far been unable to find any funeral hall or other venue where people could come to pay their respects to him.
She said one venue had told them that “funeral agencies were prohibited from working with us”.
The anti-corruption campaigner had been serving a sentence of more than three decades on fraud and extremism charges he said were trumped up to silence him.
The Kremlin has denied accusations by Mr Navalny’s family and supporters that Putin had him killed.
Allies of Mr Navalny have claimed that talks were underway shortly before his death to exchange him for a Russian imprisoned in Germany.
“Alexei Navalny could have been sitting here now, today. It’s not a figure of speech,” Maria Pevchikh, a close associate who lives outside Russia, said in a video statement posted on social media.
She said she received confirmation that the talks were in the “final stages” on February 15, the day before Mr Navalny was reported dead. However, her claim has not been confirmed.
