Size 12 Is Not Fat by Meg Cabot

Heather Wells is a former teen pop star who is now working as an assistant director of an undergraduate dorm, I mean Residence Hall. As if dealing with being dumped by her boy-band boyfriend and rooming with his hunky, older, PI brother isn't enough, now there are girls mysteriously dying at work. Can Heather solve the mystery before another girl dies?

The first in the Heather Wells mystery series.

Highly Recommended