"TRIANGLE" SONG

Since there was a "Dreamland" song question, I figured I’d throw this one out there, too, regarding some music in the "X-Files" episode called "Triangle." In the fight scene, on the Queen Anne, there is a song playing. It’s a big band song also not listed in the credits. Later in life, that identical song was also played in the third Harry Potter movie ("Prisoner of Azkaban"). Some say it’s a John Williams theme variation of "Sing Sing Sing," or "Swing Swing Swing," but none of those songs sounds like this one. The song in “Triangle” is much better.
I was wondering if you had any insight into what this song is and, if so, where I could get a copy. I’d pay, I’ll bribe, I’ll beg, whichever. I just want the search for this song to end. I’ve been wondering since the episode came out.
Ryan
Porter, IN
 
I'll try to find out, but if anyone knows the answer in the meantime, please pass it along.