One of the arrested guards is no longer in service.
Another eight guards were suspended from public duty in relation to the probe.
Prosecutors said they uncovered the alleged wrongdoing via wiretaps and video surveillance.
They said the mistreatment was repeated and dates back to at least 2022, adding they were also investigating a case of alleged attempted sexual violence on an inmate.
The Uilpa union representing prison guards expressed “dismay”, while voicing faith in the judiciary and the hope that the officers involved would be cleared.
Uilpa Chief Gennarino De Fazio said the case should also draw attention to the “dysfunctionality of the penal system”, saying it does not provide guarantees “for inmates, nor guards”.
ANSA
