This was announced by Russian news outlet Kommersant citing its own sources.
The information has been confirmed by Censor.NET's own sources familiar with the investigation. They say the investigation is aiming at interviewing several other former MPs of Russian State Duma.
Kommersant reported that Denis Voronenkov himself contacted Ukraine's Prosecutor General Yurii Lutsenko and testified in the Yanukovych case.
He confirmed some of the testimonies earlier provided by another former Russian MP Ilya Ponomarev, who was granted the status of permanent resident of Ukraine in summer 2016. Ponomarev several times met with Ukrainian investigators, including Chief Military Prosecutor Anatolii Matios, in December and January. He told the investigators of some alleged agreements between Yanukovych and the Russian leadership.
Two former Russian MPs have been interviewed within the high treason case against ex-President of Ukraine Yanukovych. This was announced by Prosecutor General Lutsenko in mid-January.
In December 2016, Ukrainian media reported that Denis Voronenkov and his wife Maria Maksakova moved to Kyiv. Russian Investigative Committee suspects Voronenkov in organization of a building embezzlement in Moscow downtown.
Censor.NET received no response from Voronenkov.