JR could have also been just plain jealous of Teghan -- jealous of the attention that HR paid to Teghan instead of him. I don't know if that was ever mentioned as one possible motive, but I certainly thought of it early on in the case.
Years ago, in the apt bldg where I lived, my across-the-hall neighbor, who was also a good friend of mine, had a boyfriend, a talented & up-and-coming journalist, who was jealous of a new puppy his GF (my neighbor) had brought home. Within 2 weeks, the puppy was dead due to the BF kicking the puppy down a flight of stairs. The puppy was already scared of the BF because of his deep loud voice -- the puppy peed on the floor as soon as the puppy saw him, and the BF kicked him down the stairs (on purpose? Who knows, but I think it was -- I saw it happen in the hall between our apts). It was never mentioned after the day it occurred. That's all I'm able to say -- I have never mentioned it to anyone until today. They moved out of state & I lost contact with them -- that was way before FB and the interwebs. Never have forgotten it, obviously. The Green Monster aka jealousy. What a horrible day.