A daughter of Mukhtar Ablyazov, a Kazakh opposition activist, is to file a criminal complaint against three diplomats, accusing them of complicity in kidnapping his wife and six-year-old child in Italy.
The complaint - to be lodged by lawyer Astolfo di Amato, a former judge of Italy's supreme court, on Wednesday - seeks to strip the Kazakh envoys of diplomatic immunity and represents an escalation of a case that rocked Rome's coalition government and led to a serious deterioration of relations with Kazakhstan.
"The complaint is based on damning evidence that the three diplomats played crucial and active roles in the aggravated kidnapping," lawyers for the family said . The envoys could face 15-year jail sentences if convicted.
The case is being filed by Madina Ablyazova, the couple's eldest daughter.
Alma Shalabayeva, and her six-year-old daughter Alua, were deported on a private jet to Kazakhstan, paid for by the Kazakh embassy and accompanied by two of the country's diplomats, on May 31 after they were seized in a raid on a villa in Rome by Italian police at the request of Kazakhstan, which was seeking the arrest of Mr Ablyazov.
Mr Ablyazov, a former energy minister who became a critic of Kazakhstan President Nursultan Nazarbayev, fled the country in 2009 when BTA bank, where he was chairman, was nationalised. Kazakh authorities said he was wanted on charges of bank fraud, involvement in an organised criminal group and money laundering.
Mr Ablyazov, who rejects the charges as politically motivated and has been granted political asylum in the UK, was not in Rome when the villa was raided. He was arrested in France in July at the request of Kazakhstan and is being held in prison pending the outcome of extradition hearings that could take a year to complete.
The UN office for human rights in Geneva said the "unlawful" deportation of Ms Shalabayeva amounted to "extraordinary rendition". An Italian government inquiry found that due process was not followed and revoked the deportation order. Rome has asked Kazakhstan to allow Ms Shalabayeva and her daughter to return to Italy. Kazakhstan has refused, saying she faces charges of forgery, and has threatened economic retaliation, if the crisis were to escalate, according to officials involved in the diplomatic stand-off.
Mr Di Amato told the Financial Times that there was a precedent for stripping the Kazakh ambassador, Andrian Yelemessov, and his two colleagues of their immunity. In the case of the "extraordinary rendition" of a radical Egyptian cleric known as Abu Omar from Milan to Egypt in 2003, Italy's supreme court stripped suspected agents of the US Central Intelligence Agency of their diplomatic immunity and they were tried in absentia and handed jail sentences.
Mr Yelemessov has denied involvement in kidnapping and says Kazakhstan was seeking the arrest and deportation of Mr Ablyazov.
The Ablyazov family could also proceed to file criminal complaints against Italian officials involved in the deportation, although Mr Di Amato said there was no evidence that Angelino Alfano, the interior minister, was responsible. Mr Alfano denied knowing about the police operation and survived a parliamentary vote of no-confidence in July that risked splitting Italy's coalition government.
Italian authorities initially justified deporting Ms Shalabayeva on the grounds that she possessed a forged passport from the Central African Republic, which later confirmed that the document was genuine. Kazakhstan chartered the private plane for her flight because there were no direct flights between Rome and the country.
Kazakhstan is also putting pressure on Spain to extradite Mr Ablyazov's former bodyguard, Alexandr Pavlov. People with knowledge of the case said the UN has privately urged the Spanish government not to comply because of fears that Mr Pavlov would be tortured if he was returned. Madrid is expected to make a decision on Friday. The UN declined to comment on Tuesday.
Lawyers for Ms Shalabayeva said documents released by the Italian interior ministry revealed an "audacious abuse" of Interpol by the authorities in Kazakhstan in requesting her deportation, even though she was not subject to an arrest warrant from the international police organisation. Kazakhstan has insisted that it did not request her extradition.