Council of Europe/ Candice Imbert

Thorhildur Sunna Ævarsdóttir, the Chair of the PACE Committee on Legal Affairs and Human Rights, has welcomed in principle the exchange of prisoners between Ukraine and the Russian Federation.

At the same time, she insisted that Volodymyr Tsemakh, a "person of interest" regarding the downing of flight MH17, who was included in the exchange at Russia's request, must remain available to the Dutch authorities investigating the case.

"The fact that Ukraine allowed Mr Tsemakh to travel to Russia does not mean that he is no longer required to co-operate in the investigation of this terrible event. Russia is a member State of the Council of Europe and as such is legally bound to fight impunity," she said.

The chair added that in early October, the committee "will appoint a Rapporteur mandated to assess the progress made in investigating this tragedy and holding to account those responsible."

Read alsoDutch prosecutors ask Russia to extradite MH17 suspect Tsemakh

As UNIAN reported earlier, Ukraine's spec-ops forces managed to detain Tsemakh in the Russia-occupied town of Snizhne in late June.

Tsemakh was reportedly a commander of an anti-aircraft unit in occupied Donbas back in 2014. In addition, Ukrainian law enforcement agencies suspect Tsemakh of involvement in a terrorist attack, which killed four Ukrainian soldiers.

In late August, Bellingcat founder Eliot Higgins suggested that Tsemakh was on a list of detainees for a major Ukraine-Russia prisoner swap. At the same time, Tsemakh's lawyer Roman Hontarev told UNIAN he was not aware of this.

The SBU declined to comment on the issue.

On September 5, Kyiv's Court of Appeals ruled to release Tsemakh on personal recognizance. Under a court ruling, he was supposed not to leave his place of permanent residence in Russia-occupied Donbas.

On September 7, Tsemakh was transferred to Russia as part of the prisoner swap between, as a result of which 24 Ukrainian sailors and 11 Ukrainian political prisoners returned home.

Ukrainian President Volodymyr Zelensky and SBU Chief Ivan Bakanov said Tsemakh had been interrogated by Dutch investigators before the prisoner exchange.