A former Texas prison sergeant is slated to stand trial, accused of throwing a handcuffed prisoner onto a concrete floor so viciously that the inmate died.

Lou Joffrion slammed inmate David Witt in August 2017 in an attack that was captured on video at the Darrington Unit in Rosharon, south of Houston.

Joffrion resigned two days later after being recommended for termination, said Jeremy Desel, a prison spokesman.

Joffrion will stand trial in September on an aggravated assault charge. He wasn't charged with murder, partly because the assault charge would be easier to prove, the Houston Chronicle reported. The charges carry the same sentencing range.

Just weeks before the attack that was caught on video, state officials said Joffrion had completed six months of disciplinary probation for another violent encounter with the 41-year-old Witt.

Prison officials Monday condemned Joffrion's conduct but noted a powerful painkiller in the slain inmate's blood as a possible cause of the altercation.

"While the use of force was deemed excessive in the investigation," said Texas Department of Criminal Justice Executive Director Bryan Collier, "an autopsy of offender Witt did find the presence of fentanyl, an extremely powerful synthetic opioid, which could explain the actions which prompted the use of force."

Witt's family members said they weren't informed of the circumstances surrounding his death for months. Officials didn't report Witt's death as a homicide until the full autopsy was completed a year later.

It's unclear whether the drug was smuggled illegally into prison or given as treatment at the hospital, where Witt had undergone surgery prior to this death. Prison officials did not further elaborate.

Connie Williams, the lawyer representing Joffrion, said his client followed proper procedures.

"There are some suggestions that he slammed him too hard," Williams said. "But there was no intent to kill anybody."

Witt had suffered from mental health issues before he was imprisoned, his family noted. He was charged with aggravated robbery in 2004, resulting in a 20-year prison sentence.

He was in and out of the system's psychiatric prisons during the first few years, according to his mother. Occasionally, she would visit the prison and Witt couldn't recognize who she was. In other instances, Witt wouldn't recognize himself.

"He was such a sweet man," Rosemary said. "And prison destroyed him."

___

Information from: Houston Chronicle, http://www.houstonchronicle.com