"MacDonald's fatal flaw was that he thought, as usual; that he was smarter than everyone else and that he could concoct a story that would exonerate him.....but the facts and evidence had him trapped and he will remain
in prison without an admission of guilt and sincere verbal contrition for what he has done ... "
Bob and Pep Stevenson
Christina Masewicz
Initially he must have thought he'd got off with it ... it took them about ten years to eventually put him where he so obviously belongs.
He got off with it for a long time, because , at first, his parents in law supported him to the hilt. Then, (as in the Bamber case), they began to suspect him, and pestered Law Enforcement until they took notice, and brought him to trial (in much the same way as Ann Eaton and others pestered the Essex police).
MacDonald could get parole if he would confess his guilt, but he refuses to. He says he would rather stay in prison for the rest of his life, than confess to murders he hadn't done.