Three secrecy-shrouded probes led by former London police Commissioner John Stevens previously identified Nelson as an army agent and Stobie and Barrett as police informers within the UDA.
His first probe exposed Nelson, who in 1992 pleaded guilty to 20 criminal charges, including conspiracy to murder, but not directly to involvement in the Finucane killing. He died six years after his 1997 parole.
Commissioner Stevens’ final investigation in 2003 spurred Barrett’s confession and conviction.
Commissioner Stevens said his three probes in total produced 9,256 written statements, 10,391 documents exceeding 1 million pages, and 16,194 exhibits of potential evidence — virtually none of it made public, all of it open for Mr. de Silva to examine.
The UDA killed more than 250 people, mostly Catholic civilians, before calling a 1994 cease-fire, renouncing violence in 2007, and disarming in 2010.
But the outlawed group still exerts influence today in many working-class Protestant communities, and police say scores of UDA members have helped stoke street clashes with police over the past week in Belfast and several predominantly Protestant suburbs.
About 30 police have been injured and 30 Protestant militants charged with rioting.