[Marc]

Originally Posted by Shaun

She opened it with relief, and all that the clue contained was a large, red letter on a post-it note: the letter X.
Tina pocketed the note and ran back outside, straight into the waiting taxi.

First task, we know this clue is 100% accurate because both died.

MAPLE LEAFS is true if Mollie isn't the killer

and this Pull me -D is true because Shaun wouldn't make it a red herring because he'd be saying... Destiny is the killer but the clue of D is wrong so that would completely contradict the clue.