The posters -- featuring Tsarnaev and his mother, the phrase "not guilty" with a version of his story and an appeal for online donations -- were first seen after Russia's May Day celebrations Wednesday, the BBC reported.
Members of the Tsarnaev family are ethnic Chechens but have lived mostly outside Chechnya, a breakaway part of Russia.
Pro-Tsarnaev leaflets have been seen in Bishkek, the capital of Kyrgyzstan capital, Russia's Interfax news agency reported.
The latest poster in Grozny claims the case against Tsarnaev in Boston is "a groundless accusation, there is absolutely no evidence against him," the BBC said.
NBC reportedly holds celebs hostage to Jimmy Fallon's show
Boston schools pull out free condoms over wrapping complaints