How to decline an interview at a school even if I haven't committed to one yet

[nkbkwrm]

I had a skype interview a couple weeks ago with a professor at one of the schools I applied to that I thought went pretty well. Later, by some random miracle I got accepted into 3 other schools that are my top choices and I am now deciding between. I wasn't sure whether I was still in the running for this earlier school I had a skype interview with (due to me drawing incorrect conclusions from stalking this website ) but I just got invited to interview there. I am not going to go to this interview because it'd be a waste of their money and time on me since I have other offers and will not consider this school anymore. I plan on sending a generic email to the admin assistant declining the invitation to visit and asking them to remove me from consideration.

My question is what should I email the professor I interviewed with? Most recs for personal declining emails to professors say to just be straight about the program I am choosing. But I haven't picked where I'm going yet and won't know until my last visit in April. Would it be cocky if I say I am considering two other schools instead and name them? I don't want to insult this current school or professor. But also the professor got his PhD at one of the schools I'm considering. I just had a very honest/direct conversation with the professor during my interview and think he deserves the courtesy of my transparency, I just don't want to accidentally offend or come off pompous.

[nkbkwrm]

If anyone is interested, I ended up just being generic and saying I will be going to graduate school elsewhere. A good phrase I used is "no longer will be pursuing graduate opportunities at X university." Took me 5 hours to come up with that phrase

[betun]

Yes, a generic phrase was fine here and your phrase does the job. Being transparent with the professor would not have hurt either as long as you did not specifically illustrate why you think they are better choices than his university.