Meighan, himself a small-time firearms dealer, later claimed to have given a full account of the conspiracy, including the £13,500 (equivalent to £140,000 today) Newton was allegedly promised in return for carrying out the killing, to Scotland Yard in 1978.
In the statement, which despite subsequent efforts to retrieve it has never been found, Meighan said Newton was given a converted Mauser pistol, which he used to shoot Scott's Great Dane Rinka before allegedly turning the weapon on her owner.
Allegedly, the gun jammed, allowing Scott to escape.
Two years after Meighan's 2014 'confession', Gwent Police launched Operation Velum to investigate his claims.
However the probe was dropped by the Crown Prosecution Service in 2017, after information supplied by the force suggested a number of key witnesses - Newton included - had passed away.
The discovery that Newton, now 71, has been living a double life in Surrey reopens old wounds - not least for Norman Scott, still alive and still demanding to know why neither Meighan or Newton were ever brought to justice.
It has also led officers from Gwent to reopen Operation Velum, although a spokesman for the force was not available for comment.
Neighbours of Newton's partner, a retired nurse, spoke of their dismay and shock at the discovery, and insisted: "He seemed normal to me. Just that, normal."
A second neighbour said Newton's partner, "the sweetest, loveliest person or neighbour you could ask for", had lived at the house for some years, and that he had started to visit her within the last two years.
