Former Los Angeles County Sheriff Lee Baca withdrew his guilty plea Monday to a charge of lying during an FBI investigation into the county's jails, opting instead for a trial, reports the Los Angeles Times .

In deciding to walk away from the agreement he struck with federal prosecutors, Baca opened the door to the government bringing a broader and more serious case against him that could include charges of obstruction of justice and conspiracy in addition to the lying allegation.

Michael Zweiback, one of Baca's attorneys, said he expected prosecutors to level the more serious charges, which mirror those brought against Baca's former second-in-command, Paul Tanaka, who was convicted earlier this year in an obstruction-of-justice case stemming from the same FBI investigation.

Baca's decision came after U.S. District Judge Percy Anderson said last month that he would reject the plea deal, which had limited the former sheriff's prison time to a maximum of six months. Anderson had sentenced Tanaka to five years in prison.

After withdrawing his plea, Baca told a horde of reporters on the steps of the downtown courthouse that he had done so because of "untruthful statements" made by the judge and prosecutors about his involvement in a scheme by sheriff's officials to thwart the FBI's jail probe.

He did not specify what was untruthful. Instead, reading from a prepared statement, Baca referenced his recent diagnosis with Alzheimer's disease and said the inevitable progression of the illness had injected an element of urgency into the case.

"I need to set the record straight about me and the Los Angeles County Sheriff's Department on the misleading aspects of the federal investigation while I am capable of doing so," said Baca, who retired in 2014.