Authorities named the victims as Joshua Wetzler, 32, and Tommy Welch, 31, after the discovery Sunday of shallow graves behind a redbrick house on suburban Knob Hill Drive in Clemmons, North Carolina. Police arrested the residents, Pazuzu Illah Algarad, 35, and his self-proclaimed wife Amber Burch, 24, in connection with the murders, and later charged a third person, Krystal Matlock, 28, as an accessory after the fact.
"We are trying to identify the circumstances that occurred," Forsyth County Sheriff Chief Deputy Brad Stanley tells PEOPLE. "At least we have stopped the chain of violence."
Algarad – the former John Lawson – legally changed his name to reference a demon in The Exorcist, and had a split tongue, a body covered with 666 tattoos, and teeth filed into spikes. "He told me he practiced Satanism," says neighbor Keith Bryson, who lives across the street from the house with the skull image permanently affixed to a black front door.
David Rolfe / Winston-Salem Journal / Polaris
When Lawson and his parents moved in, "they seemed like a regular family with a young boy, but over the years the boy went astray," says Bryson. "How did we not know that there were bodies buried across the road?"
For more on the mystery, pick up this week's issue of PEOPLE on newsstands Friday