If you read thru the suspect’s boyfriend’s Tweets, they suggest he may have had a crush on the dead woman. He gushes over how wonderful she is, then was. Perhaps the chubby girlfriend / campaign aide became jealous or imagined a relationship between her boyfriend and the dead woman.
I kinda think you are correct....toss in some possible drug-use of some type, and she might have gotten an imaginary view of the dead gal’s situation with the BF.