A Russian serial killer has murdered two women in what appears to be part of a sick and twisted protest about the incarceration of punk stars PUSSY RIOT.

The women, aged 76 and 38, were found stabbed to death in Kazan, Russia, under the phrase 'Free Pussy Riot' which was scrawled in blood on the wall behind them.

Three members of the punk feminist group were sentenced to serve two years behind bars earlier this month (Aug12) for hooliganism after staging a protest gig targetting Russian leader Vladimir Putin at a Moscow church.

Pro-Putin supporters insist the brutal murders demonstrate how Pussy Riot's songs and gigs fuel radicalism.

The band's lawyer has denounced the killings as "horrible".