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The official noted that Ustymenko had served in the SBU’s Crimea-based directorate and transferred to the Odesa directorate in 2014, being dismissed shortly, on April 29, 2014, for health reasons. Hluhovskiy added that the man was part of SBU’s Alpha task force.

"There has been no interaction [between former employee and the agency] after his dismissal from the Security Service," the SBU deputy chief said.

Read alsoSBU says operative from site of Sheremet murder had been dismissed in 2014Hluhovskiy stressed the fact that the investigation is being conducted by the National Police of Ukraine, while SBU operatives, who are embedded with the operational-investigative group, do not report to the SBU headquarters on the progress of the probe.

Hluhovsky claims that all data collected by the Security Service in the Sheremet case was forwarded to the National Police.

At the same time, the investigative journalists, who also attended at the meeting, challenged the claim, saying that some drives with CCTV data had not been submitted to the police.

Referring to the data of the National Police, Committee Chair Viktoria Syumar noted that Ustymenko had been questioned on Monday. The man is reported to have testified that he was conducting surveillance of "a certain person who is not related to the [Sheremet] case, according to the police."

None of the representatives of the National Police and Prosecutor General’s Office joined the Committee hearing.

The Organized Crime and Corruption Reporting Project (OCCRP) and on Wednesday, May 10, released the documentary where they claim an agent working for the SBU was present near the scene when the explosive device was being planted under the driver's seat of a car in which Sheremet was blown up. The investigation says that Ustymenko had been working for the SBU at least until 2014.

Read alsoEx-SBU operative spotted by journalists near Sheremet's house on night before assassination reports for police for questioningSBU press secretary Olena Gitlianska earlier said in a statement that Mr. Ustymenko had been dismissed from service April 29, 2014.

Chairman of the Security Service of Ukraine Vasyl Hrytsak stated that Ustymenko had not been on any mission near Sheremet's house on the night before the journalist’s murder, adding that the man was dismissed due to health issues and that the Agency did not trace his after-service history as there was no need for such action.

Pavel Sheremet was blown up in a car downtown Kyiv on the morning of July 20, 2016. Prosecutor General Yuriy Lutsenko called the main version of the journalist’s murder a revenge for his professional activities. Interior Minister Arsen Avakov did not rule out the version that it could be Russian authorities behind the assassination.

In February 2017, the police said that as part of the investigation into the murder of Sheremet, more than 1,800 people had been questioned. It was also reported that for the time being, there were no suspects in the case.

On May 15, former SBU operative Ihor Ustymenko was summoned to the National Police for an interrogation, the police press service told UNIAN.