The man insisted in a jailhouse interview Monday that he only wanted to talk to the teen and prove his innocence but said he was overcome by "demons" once they were face-to-face.
Franklin B. Davis, 30, of the Dallas suburb of Irving, was charged with capital murder Sunday in the death of Shania Gray. Gray was last seen alive Thursday afternoon at Hebron High School in nearby Carrollton. Her body was found Saturday in a secluded area near the Trinity River.
Carrollton police say Davis confessed to arranging a meeting with Gray under false pretenses, driving her to a trail near the river and shooting her twice with a .38-caliber pistol. According to an arrest affidavit, Gray fell into the river and called Davis by his nickname: "Why, Wish?"
Davis told police he then stepped on her neck until she stopped breathing, the affidavit said.
Carrollton police spokesman Jon Stovall said in an email that police believe Davis killed Gray because she was about to testify against him.
A spokeswoman for Gray's family, Sherry Ramsey, told The Dallas Morning News that Gray met Davis when she babysat his two children. Ramsey said that later, after the teen declined many requests to babysit, Gray told her grandmother that Davis had raped her.
The crime was reported to Mesquite police, and Davis was charged with four counts of sexual assault of a child. The trial was scheduled to start next month.
Ramsey said Davis had warned Gray he would kill her if she told anyone about the assault.
According to an arrest warrant, Davis contacted Gray through social media and pretended to be someone else in an attempt to get information about the sexual assault case. Davis then used a pre-paid cellphone to set up a meeting with Gray at her high school on Thursday.
Davis told WFAA-TV in a jailhouse interview that he tracked Gray down because he wanted to prove his innocence in the sexual assault case.
"I needed to get some kind of evidence, some kind of proof myself to show I did not have sex with her and that she's lying," Davis told the television station. He said he didn't intend to harm Gray but was overcome in the moment.
"I was fighting demons," Davis told the station. "It was like a different person was in me. It wasn't me."
Davis told authorities that Gray was surprised to see him but got into his car when he told her he wanted to talk to her about the sexual assault case. He said he then drove her to the remote area.
Stovall said police believe Gray was killed within an hour after she was picked up.
Karen Permetti, spokeswoman for the Lewisville Independent School District, told The Associated Press that Gray had enrolled at Hebron High School on Wednesday and attended school for two days. She was a junior.
Permetti said district officials weren't aware of any threats against Gray and heard about her upcoming testimony only after her parents filed a police report Friday.
Davis was being held in the Dallas County Jail on $2 million bail. Attorneys listed for him did not return messages left Monday by The Associated Press.
Hundreds of friends and well-wishers joined Gray's parents at a candlelight vigil Monday night outside Horn High School in Mesquite, where she previously attended.
KTVT-TV of Dallas and Fort Worth reported that one student was taken to a hospital after her friends said she was crying so hard that she had a seizure.
"This hurts me to my soul," close friend Janell Brown told the station. "This is the most tragic thing I've felt in my young age."
"Focusing on a man like that, or the likes of a man like that, is not how we want to remember her," Shelby Holland, Gray's junior varsity basketball coach at Horn, told KDFW-TV of Dallas and Fort Worth. "We want to spend our time talking about the hugs she was constantly giving out, the wonderful life she held for us while she was here. To see the kind of kid she was and that untapped potential for the kind of woman she would become – it's just sad to sit here and think, `We'll never know what kind of great young woman she'd become.'"