FictionOnlyReader
I think this was probably just a Death Eater sent by Voldemort to ruin the relationship between the Ministry and the Invisible Vigilante. Future-Quinn already told us that he gave up this identity. Willingly or unwillingly. If his reputation was ruined with this stage from Voldemort, then Quinn probably saw the identity as a disadvantage.
Good idea plot wise but feels bit forced. No one got suspicious over the usage of a wand during the execution? Or lack of Ice magic? Then there is the magic dammed usage of Imperious mind control that’s clearly somebody else’s playbook. Hint: likes to go by Dark Lord. Unless their incompetence is being highlighted. Especially the whole not caring about the motive or how nothing makes sense.