A panel of five appeal judges is deliberating on whether to acquit the late Abdelbaset al-Megrahi over the Lockerbie bombing after the conclusion of the third appeal against his conviction.
Lord President Lord Carloway closed oral hearings on Thursday at the High Court in Edinburgh, sitting as the Court of Appeal.
He said the panel will issue a written opinion “as soon as it possibly can”.
Former Libyan intelligence officer Megrahi, who was found guilty in 2001 of mass murder and jailed for life with a minimum term of 27 years, was the only person convicted of the attack.
The court heard on Thursday that trial judges were fully entitled to infer Megrahi was involved in the Lockerbie bombing.
Advocate depute Ronald Clancy, for the Crown, said Megrahi’s use of a false passport to travel to Malta – from where the plane carrying the bomb left just before the atrocity – taken along with other evidence, combined to form a pattern that suggested his involvement.
Megrahi’s original trial was held at a special Scottish court sitting at Camp Zeist in the Netherlands.
Mr Clancy said a number of factors suggested his involvement, including his use of a false passport.
An appeal against Megrahi’s conviction was lodged after the Scottish Criminal Cases Review Commission (SCCRC) referred the case to the High Court in March, ruling a possible miscarriage of justice may have occurred.
Judges then granted his son, Ali al-Megrahi, permission to proceed with the appeal in relation to the argument that “no reasonable jury” could have returned the verdict the court did, and on the grounds of non-disclosure of documents by the Crown.
Claire Mitchell QC, representing the Megrahi family, said on Wednesday that the case against him hangs on the date of purchase of the clothing later found in a suitcase containing the bomb and whether it was December 7 1988 or another date.
Mr Clancy said the Crown never claimed it was “December 7 or bust”.
Mr Clancy said that ignores the “important point” that the dock identification was “simply the last of a series of consistent resemblance identifications going back to February 1991”.
Gordon Jackson QC, also for Megrahi’s family, said on Wednesday that undisclosed documents in possession of the Crown revealed the witness had expressed frustration he would not be compensated for his part in the case.
He argued if the defence team at the time had known about this they would have found other documents that show Mr Gauci expressed an “interest in receiving money” and they could then have attacked his credibility, rather than take a “softly, softly” approach to questioning.
Mr Clancy claimed this evidence actually had the opposite impact, in showing that the witness did not expect any compensation and so was not motivated by it.
He said: “What this passage shows is that by June 1999, Tony Gauci was accepting of the position that he would not be compensated for the disruption to his life occasioned by the involvement in this case.
“In so far as it’s an expression of present intention, it’s the opposite of an interest in reward or compensation.
“It’s a sense of frustration that there will be nothing on the horizon.”
Mr Clancy also told the court the trial defence team knew there was a danger of Mr Gauci firming up on his position if they had not taken a soft approach, so disclosure would be unlikely to have changed their strategy.
Megrahi’s first appeal against his conviction was refused by the High Court in 2002 and was referred back five years later after an SCCRC review.
He abandoned this second appeal in 2009, shortly before his release from prison on compassionate grounds while terminally ill with cancer.
Megrahi returned to Libya and died in 2012.