ST. LOUIS — Gary Kaplan, whose BetOnSports grew to be one of the largest online gambling operations before collapsing under prosecution, was sentenced Monday to 51 months in federal prison.

U.S. District Judge Carol Jackson gave Kaplan, 50, the maximum under the terms of an agreement made when he pleaded guilty in August of racketeering conspiracy, violations of the wire wager act and conspiracy.

He likely will serve a little more than one year behind bars after receiving credit for the 31 months he was held pending trial. A few more months may be shaved off for good behavior, lawyers said.

Kaplan must forfeit $43.65 million earned through the gambling enterprise. In addition, $7 million from two accounts of his brother and sister also will be forfeited.

He still has "tens of millions" of dollars in Swiss bank accounts, Assistant U.S. Attorney Steven Holtshouser said.

Jackson said Kaplan intentionally ignored U.S. laws and deserved what he got. "He made a gamble," she said, "... and this is the payoff."

The judge also cited Kaplan's two felonies from years ago — for bookmaking and forgery — and his efforts to avoid arrest.

"Regardless of how people feel about sports betting or wagering, these are criminal laws that have to be respected," she said.

Kaplan, in an orange jumpsuit with his legs shackled, apologized for the pain and embarrassment to his family, and said he has "paid a monumental price."

One of his lawyers, Art Margulis, said the sentence was fair.

Kaplan's attorneys had argued for a short stint under house arrest, citing his contributions to charities while jailed. Gamblers who lost money when BetOnSports collapsed are not eligible for restitution, although some may recover a small portion of their money as part of the liquidation being handled in Antigua.