Updated at 7:10 p.m. with statements from Sen. Carlos Uresti and Texas GOP Chairman Tom Mechler.

AUSTIN — A federal grand jury issued two indictments against San Antonio Sen. Carlos Uresti on Tuesday, including fraud charges related to his involvement with a now-bankrupt oil company accused of defrauding investors — Four Winds LLC.

A report from the U.S. Attorney's Office for the Western District of Texas said Uresti and top officials at the company developed an investment Ponzi scheme to market fracking sand used for oil production and made false statements to entice investors in the firm.

Uresti, a Democrat who has served in the senate since 2006 and was a state representative from 1997-2006, was charged with multiple counts of wire fraud and securities fraud relating to his involvement with Four Winds. Each charge carries up to 20 years in federal prison upon conviction. He also was charged with being an unregistered broker and conspiracy to commit money laundering.

"The charges against me are groundless and I look forward to proving my innocence in a court of law at the appropriate time," Uresti said in a prepared statement. "I will enter a plea of not guilty and immediately return to work representing District 19."

Uresti is expected to appear before a federal judge in San Antonio Wednesday morning.

The San Antonio Express-News first reported on Uresti's involvement with the company in August. Uresti, a personal injury attorney, secured a $900,000 investment from one of his former clients for the company, where Uresti was paid commissions for drawing in investors.

Stanley Bates, the chief executive officer at Four Winds, and Gary Cain, a consultant for the company, were also charged with conspiracy to commit wire fraud and money laundering.

FBI and IRS officials were seen raiding Uresti's San Antonio law office earlier this year as part of their investigation into the oil company.

Under a separate indictment, the grand jury charged Uresti and Vernon Farthing, a Lubbock doctor, with paying for and accepting bribes in an effort to secure a medical services contract for Farthing's company with the Reeves County Correctional Center.

Farthing reportedly paid Uresti $10,000 a month to be his marketing consultant, but half of that money was given to an official in Reeves County for his support of Farthing's contract, according to the U.S. District Attorney news release.

If convicted, both Uresti and Farthing face up to five years in prison for the bribery charges and up to 20 years for charges of conspiracy to commit money laundering.

"As we inch closer to 2018, voters deserve to know that their elected officials are acting in the best interests of our state," said Texas GOP chairman Tom Mechler in a prepared statement. "Unfortunately, for Texans, (Democratic) Chairman Gilberto Hinojosa would rather welcome copious amounts of corruption in hopes of turning Texas blue, than do the right thing and rid himself of these lawless liberals."