UK businessman William Browder was briefly detained in Spain on a Russian arrest warrant. Browder, wanted by Moscow for fraud, tweeted the news from the back of a Spanish police car.

“In the back of the Spanish police car going to the station on the Russian arrest warrant. They won’t tell me which station,” Browder tweeted.

In the back of the Spanish police car going to the station on the Russian arrest warrant. They won’t tell me which station pic.twitter.com/Xwj27xC7Zd — Bill Browder (@Billbrowder) May 30, 2018

A Spanish National Police spokeswoman confirmed that Browder was detained on Wednesday morning in Madrid and taken to a police station to check on the arrest warrant, but said that police determined the order was no longer valid.

Browder posted a follow-up after he was released.

Good news. Spanish National Police just released me after Interpol General Secretary in Lyon advised them not to honor the new Russian Interpol Red Notice. This is the 6th time that Russia has abused Interpol in my case pic.twitter.com/ZonzXizvIJ — Bill Browder (@Billbrowder) May 30, 2018

While Browder accused Russia of “abusing” Interpol in his case, the international policing body disputed his claim - stating it had never issued an arrest warrant for the businessman.

“There is not, and never has been, a Red Notice [arrest warrant] for Bill Browder. Mr Browder is not wanted via Interpol channels,” the organization said in a tweet.

In December 2017, a Moscow court sentenced Browder to nine years in prison in absentia for tax fraud. Browder was also found guilty of tax evasion in a separate case from 2013.

Browder, the CEO of Hermitage Capital, made billions during Russia’s chaotic and devastating ‘shock therapy’ in the 1990s. He renounced his American citizenship in 1998 to avoid having to pay US taxes, and became a British citizen. The UK does not have an extradition treaty with Russia, which was fortunate for Browder. His Russia visa was annulled in 2005 and he has not shown up in the country ever since.

Hermitage has been repeatedly investigated for tax fraud. When Sergei Magnitsky, a lawyer hired by Hermitage, was found dead in his Moscow prison cell in 2009, Browder embarked on a global crusade to demonize Russia as a murderous dictatorship.

This resulted in the 2012 passage of the Magnitsky Act, which allows the US government to blacklist Russian officials “thought to be responsible” for Magnitsky’s death. In 2016, the law was expanded to have a global scope and blacklist any Russian officials for “corruption” or “human rights violations.” The move has repeatedly triggered protest from Moscow.

Browder’s vendetta against Russia has at times involved rather unseemly tactics: In April, he openly warned newly-appointed Dutch Foreign Minister Stef Blok that opposing the Magnitsky Act is a “career ruining position.” In response, Russia’s embassy in Canada tweeted: “Convicted criminal, fraudster and financial bandit @Billbrowder just threatened #Dutch @minbuza newly appointed minister by reminding him the fate of @AmbStephaneDion for being 'too soft on Russia'. Just wonder if it's not foreign meddling in internal affairs.”