Grand jury cleared officials of wrongdoing last week and Sheriff Adrian Garcia said his jail guards followed procedure.
ABC-13 is releasing the entirety of that video. Note: This video contains explicit language and disturbing scenes and may not be suitable for all audiences.
ABC-13 also showed the video to attorney Brent Mayr.
Now a defense attorney, Mayr was a long-time Harris County prosecutor who has presented accidental death cases to grand juries.
The video shows Lucas being restrained on February 17, 2014 as he was removed from his cell. The footage also shows Lucas' hands handcuffed and held high behind his back by a guard in black, protective body armor.
The inmate's feet were also cuffed and held high on his own back while another armor-protected guard sat on them for 20-minutes, the video shows.
Mayr paid particular attention to the portion of the video when Lucas was silent and motionless on a jail gurney with detention officers restraining the inmate.
While hard to watch, Mayr said that criminally negligent homicide has to be more than what he saw on the video.
"There's no bright line or anything that says one way or the other that this crosses the line into criminal negligence or not," he said. "It has to be something that shocks the conscience. It has to be something that amounts to a gross deviation to what an ordinary person would do under those same circumstances."
Mayr added: "It's easy to play Monday morning quarterback and say, 'They should have done this and they should have done that, maybe this could have been differently.'"
Mayr also noted that it was an unusual move for jailors to video this incident.
"You would record it because something could potentially go wrong and you want to have everything documented so you're not being accused of any wrongdoing," he said.
Lucas' family's attorney told ABC-13 Wednesday that being restrained inside the jail, surrounded by jail staffers and a medical team should lead to death.
See ABC-13's original report on the death of Lucas here.