ST. PETERSBURG, Russia -- Twenty years after democratic reformer Galina Starovoitova was assassinated, her sister says she does not believe that an infamous alleged crime kingpin who was implicated in the slaying was, in fact, behind it.

Speaking to RFE/RL on November 20, the anniversary of a slaying that stunned Russia and sent shock waves abroad, Olga Starovoitova said she hoped that those who ordered her sister's murder will be identified and brought to justice someday.

Galina Starovoitova, a prominent reformist politician who was co-chair of the Democratic Russia party, was shot dead in the stairwell of her apartment building in St. Petersburg on November 20, 1998.

In 2005, a St. Petersburg court sentenced a former Federal Security Service (FSB) officer and another man to prison terms of 20 and 23 1/2 years after convicting them of involvement in Starovoitova's killing.

In August 2015, former lawmaker Mikhail Glushchenko was convicted of "taking part in the organization of the murder" and was sentenced to 17 years in prison.

A few months earlier, Glushchenko claimed that Vladimir Barsukov -- an alleged organized-crime boss now in prison for murder and other crimes -- ordered Starovoitova's killing after she blocked him from establishing ties with a number of corrupt city officials.

Olga Starovoitova said she believed that Barsukov, who is also known as Kumarin, might have been involved in her sister's killing but that it's unlikely he ordered the hit.

She said there could be several layers of people involved in ordering and organizing the killing, adding that she suspects specific people but will not name them because she believes in the presumption of innocence and does not have proof.

Russia's security services "have always been chauvinists toward women" and particularly dislike "talkative women," Olga Starovoitova said, referring to women who speak their mind or challenge the authorities.

Referring to her sister and Anna Politikovskaya, an investigative journalist who was killed in her Moscow apartment building in 2006, she said that "talkative women" were being "shot down one by one."

She also said she had been told that her sister's killing was still under investigation.

An investigator "told me that investigation of Galina Starovoitova's murder is the second longest in Russia."

"The longest one is the investigation into the murder of [Tsar] Nicholas II" and his family, who were killed by the Bolsheviks in 1918.

Barsukov, the alleged head of the notorious Tambov organized crime group, is serving a 23-year prison term for murder, attempted murder, extortion, and asset-grabbing in cases that are unrelated to Starovoitova's murder.

Barsukov was a powerful figure in St. Petersburg in the 1990s and was vice president of the Petersburg Fuel Company.

Vladimir Putin, now president and at the time a deputy mayor of St. Petersburg, awarded the city’s lucrative gasoline concession to the company in 1994.