Look, if you're going to make a case on Brigitte at this point, this is the only way it can work.
Step 1: Scum knows investigation results are insane.
Step 2: Investigations only show unique selections.
Step 3: Scyther is revealed.
Step 4: Claim to have a Scyther even though you don't.
Step 5: When your teammate is found out and did an insane investigation, out yourself fully.
Step 6: Use the insane investigation to clear your teammate of suspicion.