Bianchi brothers and Pincarelli request protected area of Rome prison.

Three suspects in the brutal killing of Willy Monteiro Duarte, a 21-year-old beaten to death by a gang in Colleferro, have requested solitary confinement in a protected wing of Rome's Rebibbia prison over fears they will be attacked by other inmates, reports Italian news agency ANSA.

The request comes as the charges facing the suspects were upped from manslaughter to murder, in a case that has shocked and sickened Italy.

• Italy mourns Willy, beaten to death by gang

Three of the four arrested, currently in Rebibbia jail, are brothers and mixed martial arts practitioners Gabriele and Marco Bianchi, aged 26 and 24; and Mario Pincarelli, 22; with the fourth suspect Francesco Belleggia, 23, under house arrest.

On 12 September Italian premier Giuseppe Conte attended the funeral of Duarte, a Cape Verdian-Italian who died following a brutal assault after he had stepped in to defend his friend.

• Italy: Willy died of multiple injuries to chest, abdomen and neck

Witnesses described those who beat Willy as "devils, not human beings," with eye-witness accounts of the aggressors jumping up and down on the victim's helpless body.

An autopsy revealed that Duarte died as a result of 'polytrauma' - multiple traumatic injuries - to his chest, abdomen and neck, which led to cardiac arrest.

• Italian premier to attend funeral of Willy

Magistrates bave reconstructed a scene of "unmotivated and unprecedented" violence against a young man who "had nothing to do with" a fight triggered by a trivial matter.

• Italy: Bianchi brothers deny killing Willy Monteiro Duarte

The Bianchi brothers, who are allegedly well known for street violence and intimidation, have denied any role in the death of Duarte, telling prosecutors: "We never touched him."