The Baker's Dozen. The Probe Murder Investigations, #4

Private investigation specialists, PROBE, headed up by Alan and Melanie Cornish, together with SIO Ronnie Jarvis from the Metropolitan Police are tasked with identifying and catching an elusive, unrelenting assassin who has brutally murdered six male OAPs in the London area. It would appear that robbery is not the reason for the killings. So what is the real motive behind their horrific deaths?A list of names leaked from within MI6 is a precious clue to the killer's motive; but can he be found and stopped before more of his victims are murdered?