Although many police officers who were familiar with Manuel suspected him of carrying out these murders, they were unable to prove his guilt until shortly after they had searched the Smarts' residence and retraced their movements in the hours before their murder, when seven £5 banknotes Peter Smart was known to have withdrawn from his bank on New Year's Eve were found to be missing from his residence, and Manuel had been discovered to be using these same banknotes to pay for drinks in several east-end Glasgow pubs. After the police arrested his father, he confessed to eight of these murders (but not Dunn) and provided incriminating information only the perpetrator could have known.