Wire in the Blood S04 E03 Hole in the Heart

"TO CATCH A KILLER, YOU MUST THINK LIKE ONE"

Tony Hill assists the police in their investigation of a bizarre series of murders. In each case the victims - a property developer, a bishop, a judge - were brutally killed and the killers then immediately committed suicide. Tony thinks there is a connection to the Freemasons, but then realizes that they are dealing with a religious sect that glorifies suicide. He knows from the profile that the head of the sect will be a white male and from the religious symbolism that he will have six disciples, but who are they and how will they find this needle in a haystack?