JACKSONVILLE, Fla. – A onetime aide to former Democratic Congresswoman Corrine Brown pleaded guilty Wednesday to two criminal counts in connection with the federal investigation that helped end Brown's 24-year tenure in the U.S. House.

Elias "Ronnie" Simmons, Brown's former chief of staff, pleaded guilty to one count of conspiracy to commit mail and wire fraud and one count of theft of government property

Simmons, 51, will be sentenced after Brown's trial in April. He faces up to 30 years in federal prison.

"When you are confronted with facts, and you are confronted with your own conscience, then you have to make certain decisions," said Anthony Suarez, Simmons' attorney. "For my client, he decided that this process had to end and he ended it with a plea."

In court Wednesday afternoon, Simmons seemed calm and collected as he agreed to the plea deal. The News4Jax I-TEAM learned that prosecutors called Simmons' attorney Monday to offer the bargain, pleading guilty to two of the 19 counts against him. The other chargers were dropped.

"Ronnie is aware that he has a price to pay for his mistakes," Suarez said. "He is ready. He has confidence that his decision will bring him and his family peace after a long year of struggle and anxiety."

Simmons admitted that the charity -- One Door For Education -- was a sham and Brown knew that from the beginning and used her status to help raise $800,000 for the alleged nonprofit, which prosecutors said was a slush fund for vacations, luxury car repairs, concerts and shopping.

By accepting the plea agreement, Simmons will have to testify against Brown if he is called to do so.

COURT DOCUMENT: Elias 'Ronnie' Simmons plea agreement

Simmons' sister, Monica Simmons Isom, was also in court Wednesday. Prosecutors believe Simmons used his sister to help steal $735,000 in salary and benefits from the U.S. House of Representatives by falsely putting her on the congresswoman's payroll, when she was actually a Duval County elementary school teacher -- a scheme that both siblings benefited from, the government said.

The I-TEAM learned that Simmons' guilty plea doesn't clear her, and she may still be indicted.

Brown was driving back from Orlando when she got the news. She was there to receive an award for her work with transportation. Her office released the following statement:

"The Congresswoman was saddened today to hear about her long time chief of staff entering a plea of guilty. She worked with him for a number of years and he was effective in helping her to represent her constituents. She maintains her innocence and in no way did she conspire with Ronnie Simmons and or Carla Wiley or anyone to commit any crime.

"For the record, Mr Simmons proclaimed his innocence and the innocence of Congresswoman Brown since last summer when the pair were indicted and now at the eleventh hour, he has suddenly changed his mind. We look forward to our day in court where we can ask him what lead to this sudden change of heart on cross-examination; and what if any benefits were given to him that influenced his decision to plead guilty."

Brown, who was defeated in the Democratic primary last year by current Congressman Al Lawson, is due in court Thursday. Her attorney is expected to ask for a delay in her April trial.

The News Service of Florida contributed to this report.