ST PETERSBURG, Russia (Reuters) - The wife of an alleged Russian hacker facing extradition from Spain to the United States has told Reuters he is being held in solitary confinement and that he denies the accusation that he masterminded one of the world’s biggest spam networks.

Maria Levashova looks at pictures of her husband Peter, who was arrested on U.S. hacking charges in Spain in April, during an interview in St. Petersburg, Russia, July 22, 2017. Picture taken July 22, 2017. REUTERS/Jack Stubbs

Peter Levashov was arrested while on holiday in Barcelona in April, and U.S. prosecutors later charged him with hacking offences, saying he had operated a network of tens of thousands of infected computers used by cyber criminals.

The prosecutors are seeking a 52-year jail sentence, according to extradition documents seen by Reuters, and a hearing in the case is expected in Madrid on Wednesday.

Levashov, who has long been considered the likely identity of an online persona known as Peter Severa, spent years listed among the world’s 10 most prolific spammers, according to spam-tracking group Spamhaus.

His case provides a rare insight into U.S. efforts to track down and prosecute international cyber criminals. It comes at a time when Russian hackers are under intense scrutiny after U.S. intelligence officials accused Moscow of hacking last year’s U.S. presidential election in Donald Trump’s favor, something Russia denies.

The suspect’s wife, Maria Levashova, said her husband denied the accusations, but had still not seen the full charges. She also accused Spanish authorities of mistreating him at the behest of U.S. intelligence officials.

“It is clear that the actions of the Spanish and American authorities are intended to get my husband into such a state that he is prepared to sign anything, or that he simply won’t make it to court,” she said tearfully.

Speaking to Reuters in a St Petersburg cafe, she said he was being held in solitary confinement and frequently moved between prisons without notice, meaning she no longer knew where he was.

‘NO LUXURY CARS’

Attempts to appeal his extradition had been blocked, she said. He had not been allowed private correspondence with his lawyer, and multiple written requests to see the Russian consulate had been ignored or torn up by Spanish prison guards.

An official at the Spanish Penitentiary Secretariat declined to confirm that Levashov was in custody, but denied any prisoners in Spain were mistreated and said it was “impossible” for a prisoner to be denied confidential access to their lawyer.

The FBI declined to comment on Levashova’s allegations, referring questions to the U.S. Department of Justice, which did not respond to a request for comment. The Russian Foreign Ministry did not immediately respond to a request for comment.

U.S. prosecutors have accused Levashov of running the infamous Kelihos botnet, a network of infected devices used by cyber criminals to distribute viruses, ransomware, phishing emails and other spam attacks.

At times, the Kelihos network numbered more than 100,000 infected computers and was able to send over 2,500 spam emails in any given 24 hour period. Levashov charged between $300 and $500 for a million messages, according to the U.S. indictment.

U.S. prosecutors said the activity had made him rich.

But Maria, who married Levashov in 2009 and has a four-year-old son with him, said she did not recognize that description.

“We never had crazy amounts of money. There was never so much money that I had to ask him where it came from,” she said. “We lived well, but not with a huge income. No foreign properties, no luxury cars.”

She said her husband had studied computer engineering but had not worked as a programmer in the time she had known him, and mainly used computers to play online video games.

The real reason he was being prosecuted, she alleged, was because of anti-Russian feeling in the United States: “I really think it is some kind of political story.”