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COLLIN COUNTY (CBSDFW.COM) – A McKinney man has been sentenced to 40 years in prison after admitting his guilt to a number of child sex abuse and pornography charges, involving an underage girl.

Officials with the Collin County District Attorney’s Office say Rontae Thornton’s victim was the daughter of a woman he was dating. They say Thornton had been in the relationship for several years when the then 13-year-old said she woke up from a nap to Thornton having sex with her. It was then that Thornton began a relationship with the underage victim, having sex with her twice a week and making plans to “run away with her.”

The victim became pregnant with Thornton’s child when she was 14, and subsequently had an abortion.

Thornton was arrested on March 12, 2014, after a McKinney police officer stopped him for a traffic violation as he and the victim were leaving a motel around 2:30 a.m. The officer said he suspected there was some type improper relationship because of the time of night, the disparity in age of the two people in the vehicle, and the fact that they were leaving a motel.

As the police Sergeant investigated further he found inappropriate text messages, photos and videos on Thornton’s phone. After his arrest, Thornton confessed to McKinney police. Despite his confession Thornton chose to go to trial, but after the testimony of the arresting officer changed his plea from “not guilty” to “guilty.”

Judge Richard Davis sentenced Thornton to 40 years in prison without the possibility of parole for Continuous Sexual Abuse of a Child, and also handed down sentences of 10 years each for the Sexual Assault of a Child and Possession of Child Pornography, all to run concurrently.

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