KIEV, November 7 - RAPSI. The Ukrainian tax police resumed the investigation into four criminal cases against former Prime Minister Yulia Tymoshenko, Tymoshenko's defense lawyer Sergey Vlasenko said on Monday.

The criminal cases deal with the non-payment of taxes in the late 1990s when Tymoshenko was the CEO of United Energy Systems of Ukraine.

According to the lawyer, the criminal cases were closed at the early 2000s.

To date, four criminal cases against Tymoshenko are being investigated. Two are related to the UESU's activities and another case has been opened into the purchase of ambulances and the application of funds under the Kyoto Protocol.

The fourth case was launched for abuse of power in signing gas contracts between Ukrainian Naftogaz and Russian Gazprom in 2009. A Kiev district court sentenced Tymoshenko to seven years in prison on October 11. The judge declared that Tymoshenko abused her powers when she served as prime minister and issued directives regarding gas contract negotiations in Moscow, which were not properly documented, and without the government's consent.