The footage, published exclusively by Italian newspaper Domani, shows prison officers beating prisoners with truncheons, slaps and kicks, with some beaten on the ground.
The violent scenes were filmed at the Santa Maria Capua Vetere prison on April 6, 2020, the day after a riot in which inmates demanded masks and COVID-19 tests following the detection of the first coronavirus case at the jail.
Special forces were sent in to respond to the riots, according to Italian news agency ANSA.
The disturbing scenes, allegedly in “retaliation” for the protest, show prisoners being beaten from either side as they are paraded through a corridor full of the special forces officers.
One prisoner is dragged and kicked, while others are beaten as they stagger up stairs with their hands on their heads.
Many are beaten repeatedly by several baton-wielding officers at the same time.
Some are kneed or kicked in the stomach or punched in the ribs.
One helmeted officer uses a truncheon to beat a man in a wheelchair.
The brutality, captured by surveillance cameras, has led to legal proceedings against 52 prison officers and managers, who face charges including aggravated torture, aggravated ill-treatment, and causing multiple aggravated personal injuries.
A preliminary investigations judge said prisoners were made to strip and kneel, then beaten by officers wearing helmets so as not to be identified.
Some 15 men were also placed in solitary confinement without any justification, the judge said.
Police reportedly found concerning messages on the suspects’ phones including: “We’ll kill them like calves”.
The incident has proved divisive among Italy’s politicians.
Centre-left Democratic Party (PD) leader, Enrico Letta, said the video had revealed “intolerable” conduct by the officers, while far-right League leader, Matteo Salvini, showed support for those arrested.
