A Dallas jury found Franklin Davis guilty Tuesday of killing a North Texas teenager to stop her from testifying against him in a sexual assault trial.
Now the jury will begin the sentencing phase of the trial.
Davis admitted to taking Gray from Hebron High School on Sept. 6, 2012. He told the jury that he shot her twice on the banks of the Trinity River in Irving and then stepped on her throat before leaving her to die.
Prosecutors said Gray was killed to prevent her from testifying in a sexual assault case she had pending against him. Mesquite police said Davis had sex with Gray four times in 2010 while the then-14-year-old was babysitting his children.
Davis told jurors that he was overcome with rage by the accusations that he sexually abused Gray, allegations he has consistently denied.
"Shania took away all my dreams," he said.
"I had plans on being a mentor to try and help little boys, tried to convince my wife to help little girls," he said. "I planned on buying a house for my family. I planned on getting my son to come stay with me because he was having behavior problems in school, and I felt Shania turned all my dreams into nightmares when she did what she done."
Prosecutors are seeking the death penalty. They said Gray's death was a planned murder to permanently silence Gray.
His defense team disputed the rape allegations and hoped for a conviction on a lesser charge of murder and a possible lighter sentence.
NBC 5's Lindsay Wilcox contributed to this report.