Chief Military Prosecutor of Ukraine Anatoliy Matios has said that suspended State Fiscal Services of Ukraine chief Roman Nasirov has assisted in the investigation of the so-called illegal 'tax scheme' used by former tax officials throughout Ukraine.

"It took longer to investigate the case because it was impossible [for investigators] to immerse themselves in the debris of such a complicated organization that for a long time morphed into various ministries of revenues, state fiscal services and so on," Matios said in an interview with the Kyiv-based 112.ua on Wednesday evening.

He said a meeting was held after head of Ukraine's Prosecutor General's Office (PGO) Yuriy Lutsenko had sent the 'tax centers' case to the military prosecutor's office.

"The chairman from the State Fiscal Service was Roman Nasirov. We wouldn't have been able to crack the case without his knowledge of all the various components of the scheme," Matios said.

Asked whether Nasirov's contribution to cracking the case would mitigate charges against him, Matios responded: "I don't have an opinion, but only lay out the facts. Whether [Nasirov's help] could mitigate the charges against him – I do not know," Matios said.

As earlier reported, Nasirov is suspected of committing crimes pursuant to Part 2 of Article 364 of the Criminal Code of Ukraine (misuse of public office leading to serious consequences).

The National Anti-corruption Bureau of Ukraine suspects Nasirov of taking a number of unfounded and illegal decisions on repayment terms for rental payments on exploitation of natural energy reserves from May 2015 through March 2016 as part of the so-called "Onyshchenko's gas scheme." [Verkhovna Rada of Ukraine deputy Oleksandr] Onyshchenko has fled Ukraine. The scheme allegedly led to more than UAH 2.019 billion in losses to the state.

On March 2, 2017, NABU agents served a notice of suspicion to Nasirov, who was subsequently hospitalized at the Feofania clinic outside Kyiv.

Kyiv's Solomyansky District Court on March 7 remanded Nasirov in custody for 60 days and set bail at UAH 100 million. The Specialized Anti-Corruption Prosecutor's Office (SAPO), meanwhile, requested the court set bail at UAH 2 billion.

Kyiv's appeals court on March 13, 2017, ruled to set bail at UAH 100 million, which was paid by Nasirov's wife on March 16. SAPO agents next filed a motion to arrest Nasirov's property.