Prosecutors had alleged that Alexei Lashmanov, 28, had been Levin's accomplice in a scheme to penetrate Citibank's computers, steal millions from corporate accounts and transfer the funds to overseas accounts.
Lashmanov, 28, faces a possible maximum sentence of five years in prison and a $250,000 fine for participating in the scheme that involved the illegal transfer of funds to bank accounts he controlled in Israel.
Prosecutors alleged that the mastermind of the scheme was Vladimir Levin, a Russian mathematician who graduated from the University of St Petersburg and who is awaiting extradition from Britain.
Levin's father, Leonid Levin, said his son had said he does not know who Lashmanov is.
Mr Levin said St Petersburg police had questioned him about Lashmanov when they were investigating the case against his son.
Levin's father also revealed that his son had asked to change his legal team at the end of December. He said Levin had claimed that one of the lawyers assigned to him was an FBI agent.
Mr Levin said his son wanted the lawyer who had handled Nick Leeson's defense in the Barings bank collapse case to defend him.
He added that his son's lawyers are paid for by the US government.
In August, the Justice Department told a British court that Levin stole $2.8 million from accounts at Citibank in New York. He was arrested in April at Heathrow Airport in London.
The department alleged that Levin, working from a computer terminal at AO Saturn, a computer company in St Petersburg, Russia, directed computers at Citibank to send the money to bank accounts in Finland, Israel, and to Bank of America in San Francisco.
The charges against Lashmanov alleged that in August 1994 he told co-conspirators in Russia about his personal accounts in Tel Aviv, Israel.
The co-conspirators had gained unauthorized access to the Citibank Cash Management System, which allows Citibank customers to access a computer network and transfer funds from their Citibank accounts to accounts at other financial institutions.
In pleading guilty, Lashmanov admitted that his co-conspirators had executed unauthorized wire transfers from Citibank customers' accounts to Lashmanov's accounts at five Tel Aviv banks.
He also admitted trying to withdraw about $940,000 in cash from these accounts.
Three others have previously pleaded guilty for their role in the scheme. Levin's father also said that his son had wanted very strongly to vote in the recent Duma elections and had called the Russian Embassy in London.
He said a consular official had promised to bring Levin a special ballot paper and ballot box but that his son had waited in vain.
Levin has complained to his parents that no one from the Russian Embassy has visited him in the almost 10 months he has spent in a London prison. (Reuter, SPP)