Two men working separately tried to steal a total of $430,000 from the personal bank accounts of billionaire Mayor Michael Bloomberg, prosecutors said. One of the men spent nearly $10,000 he stole from the mayor, authorities said.

Two banks notified authorities in June after Odalis Bostic, of Elizabeth, New Jersey, deposited two checks — $190,000 in one bank and $230,000 in the other — drawn on Bloomberg's account at Bank of America, prosecutors said Tuesday.

The checks were deposited into accounts in PNC Bank and Sovereign Bank opened by Bostic for a company he created, Manhattan District Attorney Robert Morgenthau said. The mayor's account information appeared on both checks, he said.

Because of the amounts of the checks, Morgenthau said, the banks put holds on them and notified his office. He said the investigation began when both checks were found to be forged.

The district attorney said investigators learned that Charles Nelson, in an online transaction in May, transferred $10,000 from the mayor's Bank of America account to an E-Trade stock trading account. Nelson, of Newark, New Jersey, spent virtually all the stolen cash, prosecutor Jeremy Glickman said.

Investigators have no evidence that Nelson and Bostic were working together or knew each other, and have not yet learned how the men got Bloomberg's banking information, Glickman said.

Bloomberg, whose fortune is estimated by Forbes at $11.5 billion, declined to comment through a spokesman. Morgenthau said Bloomberg was not told about the investigation until Tuesday.

Bostic, 23, was arrested in New Jersey in August and waived extradition to New York. At his arraignment Tuesday he pleaded not guilty to second-degree attempted grand larceny, which is punishable by up to seven years in prison.

His attorney, Elias Martinez, said the prosecution's case was weak.

Acting Justice Laura A. Ward set Bostic's bail at $10,000 and scheduled his next court appearance for Oct. 18.

Nelson, 31, was jailed in New Jersey on local charges, including gun possession, Glickman said. Nelson was awaiting extradition to New York to face charges of third-degree grand larceny and first-degree identity theft, he said.

Each charge is punishable by up to seven years in prison.

Prosecutors said they didn't know if Nelson had hired an attorney.