Germany's ongoing effort to pursue Ukrainian citizens it suspects of being behind explosions that damaged the Nord Stream gas pipelines faces its next battle in the high-security bunker courtroom at Bologna prison in northern Italy on October 23, following a series of recent legal and political setbacks.

The suspect identified by German prosecutors as Serhii K. won an appeal court ruling on October 15, preventing his extradition to Germany following his arrest on a European arrest warrant while on holiday in Rimini in August.

That was followed two days later by a verdict in Poland releasing another Ukrainian man, Volodymyr Z., whose extradition Germany was also seeking.

German prosecutors say the men were part of a group of divers who used a hired yacht to sabotage the Nord Stream pipelines in 2022, seven months after Russia launched its full-scale invasion of Ukraine.

Serhii K.'s extradition was blocked largely on procedural grounds. His legal team believe the ruling in Warsaw will strengthen his case.

"The novelty lies in the Polish precedent concerning an alleged co-offender in the same facts of crime, which I consider binding," said Serhii K.'s lawyer, Nicola Canestrini, in written comments to RFE/RL.

Nord Stream, majority-owned by Russia's state-controlled Gazprom corporation and co-financed by major European energy companies, was constructed to deliver Russian gas directly to Germany, bypassing transit states such as Ukraine and Poland, which had strained their relations with Moscow.

The suspected sabotage and subsequent gas leaks caused the pipelines to become inoperable.

German prosecutors have not said that the group was operating under orders from the Ukrainian government or other state authorities, and Kyiv has denied involvement.

However, the Polish court ruling said that "the person being prosecuted, if he was the perpetrator, is entitled to functional immunity, which covers an act committed in connection with his activities for the Ukrainian state."