A former Ukrainian member of parliament who has claimed to have dirt on a company linked to the Bidens was arrested earlier this week in Germany, The Daily Beast has confirmed. Oleksandr Onyshchenko, who worked closely with Ukraine’s previous president before fleeing the country after being accused of embezzlement, has been living in Europe for several years. German authorities arrested him in Aachen on Friday.

Oleg Ishemko, an attorney for the former member of parliament, confirmed the arrest.

“We are analyzing information in particular about the fact and basis for the detention of our client,” Ishemko said in a text. “According to our information, Oleksandr was in the process of seeking international protection and could not be arrested in accordance with Article 33 of the international convention relating to the status of refugees. Attorneys for Oleksandr are doing everything so that his rights, both in Ukraine and outside, are upheld in the necessary manner.”

Onyshchenko’s arrest comes as efforts by Trump’s American allies to find information about Burisma Group—where former Vice President Joe Biden’s son was once a board member—have reached a fever pitch. Rudy Giuliani, Trump’s personal attorney, is currently in Kyiv, Ukraine, holding meetings on the subject. Efforts by Giuliani and other Trump administration officials to win political goodies from Ukrainian government officials—including an announcement of an investigation into Burisma—are a central focus of Democrats’ impeachment investigation of President Donald Trump. Democrats’ next impeachment hearing is scheduled for Dec. 9.

German authorities arrested Onyshchenko based on a request from Ukraine’s National Anti-Corruption Bureau and Specialized Anti-Corruption Prosecutor’s Office (SAPO). According to a report from the UNIAN news agency, Ukrainian officials are awaiting a ruling from a German court on whether or not to extradite Onyshchenko.

After fleeing Ukraine in 2016, Onyshchenko claimed to have evidence of widespread corruption by then-Ukrainian President Petro Poroshenko, and he said he’d contacted the FBI with his claims. Two sources familiar with the events confirmed that he did meet with U.S. law enforcement officials in 2016 in an effort to build goodwill. The sources said Onyshchenko appeared to want to share information in hopes of obtaining a visa to travel to the U.S. The U.S. Justice Department confirmed meeting with him at the time but said it had “no plans to have further meetings or communications” with him after that, according to RFE/RL. His allegations were widely seen in Ukraine as part of a Kremlin-orchestrated disinformation campaign meant to undermine the Ukrainian government as it sought to strengthen ties with the West.

As the impeachment proceedings against President Trump took hold in October, Onyshchenko claimed to have inside information about Hunter Biden and his work for Burisma. He told Reuters that his friend Mykola Zlochevsky, who founded Burisma, had placed the vice president’s son on Burisma’s board as insurance against criminal investigations. The claim echoes those made by Rudy Giuliani and former Ukrainian Prosecutor General Yuriy Lutsenko. “It was to protect (the company),” he said.

In early November, Onyshchenko told the obscure right-wing news site CD Media that “there were ‘official’ and ‘unofficial’ payments to the Biden family” made by Burisma and that an FBI agent “directed the coverup of the Biden scandal at the time, in concert with the U.S. embassy in Kyiv, and other Deep State American government assets ‘in-country.’” The claim resembled the same conspiracy theories spun by Giuliani in his successful campaign to oust former U.S. Ambassador to Ukraine, Marie Yovanovitch.

In subsequent interviews, Onyshchenko made other fantastic claims, including that Burisma had paid $10 million to Hillary Clinton’s presidential campaign through “big bags of cash” sent instead of wire transfers.

On Tuesday, as news of Onyschenko’s arrest broke, CD Media published a report claiming he was “heading to the U.S.” to testify against Biden when he was arrested in Germany. The report was accompanied by a screenshot of a U.S. visa application the Ukrainian politician had purportedly submitted last week to the U.S. embassy in Budapest, Hungary.

The fugitive Ukrainian was stripped of parliamentary immunity in 2016 and accused of embezzling some $64 million from a subsidiary of Naftogaz, Ukraine’s state-owned gas company. A former member of ousted Kremlin-backed Ukrainian President Viktor Yanuykovych’s Party of Regions, Onyshchenko was also accused by Ukraine’s Security Service of treason in late 2016 of allegedly helping Russian intelligence destabilize Ukraine.

He has long denied the allegations, insisting they are the result of his criticism of Poroshenko’s administration. Shortly after fleeing Ukraine in 2016, Onyshchenko publicly claimed to have recordings with damning evidence of corruption by Poroshenko. Onyschenko even published a book with his allegations titled Peter the Fifth: True Story About Ukrainian Dictator.

Onyshchenko changed tack after the election of President Volodymyr Zelensky, writing on his personal website that he “intends to return to Ukraine and help President Zelensky in fighting the corrupt structures put into place by the old government.”

Onyshchenko is known in Ukraine as a vocal critic of financier George Soros and of the Obama administration. In his latest posts on Facebook he defends former Ukrainian prosecutors Lutsenko and Viktor Shokin–both of whom have faced criticism at home for working with Giuliani on his Burisma investigative endeavors. He has also echoed claims made by Giuliani that the U.S. Embassy in Kyiv worked against Trump’s campaign in the 2016 election, claiming evidence against former Trump campaign chairman Paul Manafort was fabricated. “The whole thing was made up in advance," he said in an interview for “112 Ukraine” television channel. “The U.S. Embassy helped to stage it.”

--with additional reporting from Allison Quinn and Anna Nemtsova