MUSKOGEE, Oklahoma - A 63-year-old Wainwright man, accused of raping an 18-year-old woman witnesses called "mentally retarded and autistic," has been found guilty on three of five felony charges.

A Muskogee County jury on Tuesday found Jerry Lee McNatt guilty of two counts of first-degree rape and one count of forcible sodomy.

He was alleged to have had repeated sexual encounters at his home between January and April 2009 with the woman, who court documents say was diagnosed as mildly retarded.

"…We're happy a rapist is off the streets, especially since he served time in California for rape already," Muskogee County Assistant District Attorney Nikki Baker told The Muskogee Phoenix. "We weren't allowed to tell the jury that."

McNatt admitted having a sexual relationship with the woman, but claimed the sex was consensual and the woman, who was 18, initiated those acts, the newspaper reported. 

Baker  told the jury McNatt breached trust developed between the two during the course of 13 years preceding the sexual relationship, and that he knew of the girl's developmental problems, the Phoenix reported.

"He waited until she was 18 (years old) to instruct her how to have sex. ... Just like a wolf attacking a little lamb," Baker told jurors, according to the newspaper.

The Phoenix said Baker cited witnesses who testified the woman was "mentally retarded and autistic." The witnesses said the woman would lose touch with reality "a hundred times a day."

Jurors acquitted McNatt of a second count of forcible sodomy and one count of rape by instrumentation.

The jury recommended 25-year sentences for each of the two rape counts and a 20-year sentence for forcible sodomy.

McNatt will be sentenced in August.