MOSCOW, May 28 - RAPSI. The investigation into the criminal case of Pussy Riot female punk group members is expected to come to an end by June 4, Mark Feigin, counsel for one of the suspects, reported in his blog on Monday.

The group of five masked female punks performed a protest song entitled "Holy Sh*t" at the altar of the Christ the Savior Cathedral in downtown Moscow on February 21. The lyrics included lines such as "Holy Mother, Blessed Virgin, chase Putin out!"

The performance video was posted online and evoked a massive public outcry.

Pussy Riot said their performance was a reaction to the Orthodox Church head Patriarch Kirills backing of President-elect Vladimir Putin in the run-up to his landslide March 4 election victory. The patriarch called the 12 years of Putin's rule a "miracle of God" in a televised meeting.

Pussy Riot first hit the headlines in January, when they raced through a musical diatribe against Putin on a snowy Red Square, calling for "Revolt in Russia!" and chanting "Putin's got scared", before being detained by police.

Three of the Pussy Riot members have been charged with hooliganism, a crime punishable by up to seven years in prison. Nadezhda Tolokonnikova, Maria Alyokhina and Yekaterina Samutsevich are currently behind bars.

Defense attorney Violetta Volkova has said that the expert appraisal revealed that the girls' actions do not qualify as a crime. It concluded that the only possible misdemeanor is the possible offence caused to believers. This kind of violation is punishable by a fine of 1,000 rubles ($34.1).

Amnesty International human rights organization has declared the three Pussy Riot members prisoners of conscience.