New York - Two guards at New York's notorious Rikers Island prison pleaded not guilty on Thursday over the death of an inmate who was beaten to death nearly three years ago.
Ronald Spear, 52, died in the early hours of December 19 2012 after being repeatedly kicked in the head while lying face down and restrained.
A current and two former corrections officers are charged over his death and covering up the assault.
Former guard Brian Coll, 45, and current corrections officer Byron Taylor, 31, pleaded not guilty as they appeared in court, according to the office of the US Attorney for the Southern District of New York.
Spear, who was seriously ill with kidney disease, was assaulted after getting into a fight with Coll about seeing a doctor, according to court documents.
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Deep-seated culture of violence
He died on the floor of a medical wing of the prison.
The guards apparently colluded to concoct a story that Spear had attacked Coll with his cane and that the inmate's death was accidental.
According to a court indictment, "Spear posed no danger to Coll or any other correctional officers".
The most serious charges against Coll - obstructing justice and filing false forms - carry a maximum sentence of 20 years in jail. Taylor also faces a 20-year sentence if convicted.
Former corrections officer Anthony Torres, 49, is also charged in connection with the death. Torres has pleaded guilty to conspiracy and filing false reports.
The case is the latest development relating to what prosecutors have called "a pervasive and deep-seated culture of violence" at what is one of the largest municipal jails in the United States.
The city of New York and federal prosecutors promised sweeping reforms earlier this week to end decades of violence against inmates, including teenagers, at Rikers Island jail.