Ratcliff, 50, was indicted in October. He was accused of offering the boy a swap of sexual favors for a nicer cell in the hospital wing when the boy was an inmate. Ratcliff told the grand jury that he didn't make unwanted or sexual advances toward his accuser.
The Victoria Advocate reported in its Friday editions that court records did not say when the sex that Ratcliff lied about happened.
Ratcliff's attorney, George Filley III, said the former sheriff and his accuser had an "ongoing sexual relationship for years."
District Attorney Pro Tem Terry McDonald said the guilty plea equaled justice.
"In a trial, it would have been a swearing match between (the accuser) and Ratcliff," McDonald said after the hearing. "Ratcliff confessed to a felony."
McDonald said he offered the plea since the primary charge -- aggravated sexual assault -- was suspected of happening in 1997 and there is no physical evidence.
The now-25-year-old man who accused Ratcliff of sexual assault was in the courtroom for Ratcliff's plea. He said he was disappointed in the plea agreement, which he told the newspaper he wasn't consulted on.
The man said he was told a plea would avoid prolonged court proceedings, which may have made him look worse or humiliate him.
"I'm not humiliated because of something someone else did," he told the newspaper.
"It further goes to show the good ol' boy system in Victoria," he said.
The accuser is currently in a correctional facility for violating his probation on a drug charge. He was on furlough from the center to attend Thursday's proceedings, the newspaper reported.
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