His mother RowVaughn Wells told CNN that she received a call from a doctor at St Francis Hospital at 4am on the day he died to say her son’s organs were failing and to come to the hospital immediately.
“He said, ‘why aren’t you here?’ And I said, ‘the police officers said that I couldn’t come, because he was under arrest’,” Ms Wells told the network. “The doctor proceeded to tell me that my son had went into cardiac arrest and that his kidneys were failing.”
Ms Wells told the network that by the time she and her husband arrived, her son was “already gone”.
“They had beat him to a pulp,” she said, adding that he had bruises “all over him”.
“His head was swollen like a watermelon. His neck was busting because of the swelling — they broke his neck. My son’s nose looked like an ‘S.’ They actually just beat the crap out of him,” she said.
Ms Wells told CNN that if her son had lived, he would have been a vegetable.
Five Memphis police officers who arrested Nichols have been fired and charged with second-degree murder.
Memphis officials plan to release the video on Friday evening, with the police chief Cherelyn Davis warning that people will see for themselves how the officers showed a “disregard for basic human rights”.
Ms Wells described the officers’ actions “heinous, reckless, and inhumane”.
Along with the clear condemnation of the officers’ actions, Ms Davis also asked the public not to respond to the footage with violence and destruction.
“I expect our citizens to exercise their First Amendment right to protest, to demand action and results,” she said. “But, we need to ensure our community is safe in this process.”
The Department of Homeland Security said it was coordinating with law enforcement in cities across the United States in anticipation of unrest after the release of the body cam footage.
Nichols’ family attended a vigil in Memphis on Thursday night.
In an open letter to Attorney General Merrick Garland, the family’s attorney Ben Crump called for an end to “saturation policing” units that were involved in Nichiols’ death.
“These types of aggressive units are used in cities across the country and are intended to flood troubled areas with officers to stem high crime,” Mr Crump wrote. “But what we’ve seen this month in Memphis and for many years in many places, is that the behaviour of these units can morph into ‘wolf pack’ misconduct that takes away a person’s liberty or freedom to move, akin to a kidnapping.”