Christopher Mackin, a 31-year-old known to police, is thought to have been shot up to four times during the incident at College Square North on Thursday night.
Switzerland set up Saturday's triumph with two straight sets victories in Friday's opening singles rubbers including a 6-0 6-0 6-2 win for Federer over British world number 262 Alan Mackin.
Earlier in the week, Det Chief Insp John McVea said the PSNI were not looking at any of Mr Mackin's "previous involvement with police as the motive for this murder".
"This is an unusual event in this area and I think the motive lies more in close associations with Christopher Mackin and I don't think it involves any of his previous criminal activity, " he added.