A Melbourne pathologist has been flown to Solomon Islands to examine the bodies of seven members of the Anglican Church religious group, the Melanesian Brothers, exhumed earlier this week on the Weather Coast of Guadalcanal.
The brothers had been taken captive by former rebel leader Harold Keke and later killed by members of his Guadalcanal Liberation Front, the GLF.
The Deputy police commissioner Ben McDevitt says they have arrested all six of the people involved in the killings.
He says they have made full confessions which he says match the evidence from the exhumation process.
Mr McDevitt says they have isolated a motive.
"We will be alleging in the forthcoming court process that the motivation would appear to be that the GLF members involved suspected that these Melanesian Brothers were spies of the government."
The Archbishop of Church of Melanesia, Sir Ellison Pogo, has previously said there is no truth in the claim the Brothers were working for the Government.