Need help with "I put a spell on you."

[InfiniteApocalypse]

I'm going to side with Mr. House this play through but I wanted to get as many quests done for both Legion and NCR before they hate me for siding with House. I just did a mission for Vulpes and got the mission 'I put a spell on you.' I favor the NCR way more than the Legion, is there any way for me to tell them they have a spy in their midst even thou I started this on the Legions side?

[Vex Hilarius]

https://fallout.gamepedia.com/I_Put_a_Spell_on_You

[InfiniteApocalypse]

I've already read that, What I want to know is if I start it on the legions side can I defect to the NCR. Thank you for the reply though.

[Vex Hilarius]

No I dont believe so.

[the big m]

nah I think you gotta start it on the ncr side, just go to the watchtower the quest marker brings you and wait until late at night and you can find the spy

[InfiniteApocalypse]

Thanks, I'll probably just kill him and let the quest fail and the NCR hate me. They'll never know the threat I took out.