John Finnegan, 48, died after it is claimed he was shot in the face in Bank Street, Neilston, Renfrewshire, on October 27 last year.
James McCarron, 33, and Francis Coates, 36, yesterday went on trial accused of murdering Mr Finnegan.
Coates' legal team have lodged a special defence of incrimination. The jury at the High Court in Glasgow was told that, if a killing occurred, it was carried out by Armour Donnell.
Donnell is said to have been paid £10,000 by William Burns – otherwise known as Basil – while acting on the orders of Stewart Gillespie of Paisley, Renfrewshire.
The court was told that Gillespie himself is now dead due to "fatal stab wounds sustained in his home" earlier this year.
Coates and McCarron – who both deny the charge – have also each lodged a special defence of alibi.
The trial, before Judge Michael O'Grady QC, continues.