not necessarily. He may, imo, have committed the murder then panicked and phoned someone he trusted to help him
So,
all who allegedly helped him are partners in crime and must be dealt with Justice system.
Period.
Better for them to contact Police, confess and lead to the victim than hide and cower in constant fear of being denounced.
Sooner or later all who might have been involved will be caught as they are certainly not criminal masterminds.
But I think he allegedly acted alone.
I would check dams/ponds/lakes/river and mineshafts in the vicinity of Mt Clear.
JMO