FORT WORTH, Texas -- A man convicted of sexually assaulting a child walked free Tuesday in Fort Worth due to a bureaucratic mistake.

Last month in Johnson County, Shaun James, 25, was sentenced to more than 10 years in prison last month on multiple counts of sexual assault of a child. He was transferred to the Tarrant County jail to face additional charges, including a DUI. Authorities say yesterday, he pleaded out and was mistakenly released.

"He should have been in custody. I take full responsibility for him walking out that door," said Tarrant County Sheriff Bill Waybourn in an interview Wednesday. "But just as soon as that error was known, we jumped on it and went to work."

The Tarrant and Johnson County Sheriffs Departments worked together to locate James, who turned himself in peacefully in Johnson County late this afternoon.

He was free for less than 24 hours, but it might have been longer if it were not for the victim's mother. WFAA is not sharing her name to protect the victim's identity, but in an interview Wednesday, she said she learned about the release last night through an app on her phone.

"I started receiving phone messages that he had been released, and his sentence had been completed," she said. "I was like, how can this be?"

Sheriff Waybourn said his department is still investigating to see what went wrong, but they believe it may have been a human error.

"They thought he was free and clear, and somewhere along the paper trail, where a human being was involved, we think somebody probably missed something," Waybourn said.

The mother began frantically calling authorities this morning, worried for her family's safety. She thinks that had she not alerted them, officials may not have known that James was free.

She said she is relieved now that he is back behind bars, but she wants answers from officials and wonders whether James will face additional punishment for walking.

"I really am questioning how this happened, and will it happen again, and has it happened to other people?" she said. "I support the blue. I believe in our criminal justice system, but this has definitely been a failure all the way around."