Three teenagers have been convicted of murder and one of manslaughter over the death of 19-year-old Liam Smith who was shot outside Altcourse prison.
Liam Smith was visiting a friend in prison when he was shot
Ryan Lloyd, 19, Thomas Forshaw, 18, and a youth, 16, all from Croxteth, had denied murder but were found guilty at Liverpool Crown Court.
Liam Duffy, 26, of Croxteth, was convicted of manslaughter.
The jury failed to reach a verdict for Anthony Rimmer, 21, of Croxteth. A retrial will be considered next month.
The trial, which lasted 10 weeks is estimated to have cost £5m and involved 11 defendants, charged with offences ranging from murder to conspiracy.
The jury was told that on 23 August 2006, Mr Smith visited a friend at HMP Altcourse in Fazakerley, Merseyside, and words were exchanged between him and Ryan Lloyd who was being visited by his sisters.
Lloyd, of Silverwell Road, Croxteth, left the visiting hall and returned to the wing and within an hour Mr Smith was shot dead.
Lloyd had made a phone call from a contraband mobile phone and was heard to say "Quick, quick, give us the phone, I'll get the boys up here to pop them", the prosecution said.
Ryan Lloyd of Silverwell Road and Thomas Forshaw of Middle Way, Croxteth, and the 16-year-old youth were convicted on Thursday and will be sentenced on 27 September.
The trial ended on Friday when Liam Duffy, of Polperro Close, Croxteth, was acquitted of murder but convicted of manslaughter.
The rest of the defendants were acquitted.
The court will resume on 3 September to consider whether a retrial should take place for Mr Rimmer, of Rimmerbrook Road, Gateacre.