Just to clarify, we can either choose to investigate a person or observe the force. For the latter, if the Sith uses a certain method to kill, we can observe a disturbance in the force and see a few who are possibly connected to it.
Villain - connected to the force
surendar (original role) - not connected to the force
observed the force - noticed no disturbance - this was the night that surendar died I believe
CaptainCremer - connected to the force
FP - not connected to the force
I have solid grounds to have suspicion on CC, all the evidence points towards it.
Rudolph's response above this only strengthens my theory of him being in cohorts with him.