Raleigh, N.C. — Two days after former House Speaker Jim Black was sentenced to federal prison for corruption, the State Board of Elections is turning its attention to $500,000 given to him seven years ago.

The money came to light Monday in court papers in which the U.S. Attorney's Office requested that Black receive a stiff sentence.

Prosecutors said a lobbyist gave him a $500,000 check in June 2000 and it was deposited in his campaign account. Black wrote a check back to the lobbyist, but shortly thereafter put another $500,000 check into his campaign account.

Black and his attorney have called the transaction a legal loan from a lobbyist to help in a real estate transaction. They said the money was paid back.

But Bob Hall, executive director of watchdog group Democracy North Carolina, which has investigated finances for years, said he believes the money is connected to the video poker industry.

"This is a politician who singlehandedly protected the video poker industry for years," Hall said. "This $500,000, I'm sure, came from a lobbyist working for the video poker industry, as one of his clients, and I wouldn't be surprised if it's video poker money."

With Black's power weakening last year as state and federal investigations closed in on him, state lawmakers passed legislation outlawing video poker machines statewide.

Neither federal prosecutors nor Hall would identify the lobbyist.

"I think this matter remains under investigation by both state and federal authorities," Assistant U.S. Attorney John Bruce said.

Professional Lobbyists Association President Susan Valauri said the allegations are another blow to her law-abiding colleagues.

"It hurts us when a lobbyist is smeared over allegations of unethical conduct," Valauri said.

Although Black will soon start serving time for corruption, Hall said he hopes authorities eventually get to the people who tried to influence him.

"It's as much about the people who are bringing it in as the politician willing to take that bribe," he said.