A man has been charged with murder after an inmate was killed in Pentonville prison.
New father Jamal Mahmoud, 21, died after being stabbed at the north London jail during an attack which left two others injured on Tuesday.
Basana Kimbembi, 34, of no fixed abode was charged with his killing on Friday, police said.
A 26-year-old man who had been arrested in connection with the offence has been released, police said.
The two other victims in the attack have non-life threatening conditions but remain in hospital.
A post-mortem of Mr Mahmoud concluded he had died from a single stab wound.
Kimbembi will appear in court at a later date.
The killing of the young father prompted calls for an inquiry into the state of jails in England and Wales, with his family accusing the prison of "neglecting him".
Cuts to staff and resources by the Government meant the "tragedy" at the north London site was "no massive surprise", t he Prison Governors Association (PGA) said on Wednesday.
It follows a slew of warnings about safety behind bars while Pentonville was last year singled out by former justice secretary Michael Gove as "the most dramatic example of failure" within the estate.