From the start of the series, it's clear that Smurf has a problem with Catherine. Because of Catherine's relationship with Baz and the obvious emotional control she has over Pope, Smurf makes a plan to get rid of her. She convinces Pope that Catherine is going to talk to the cops and snitch on the Cody boys for all of their crimes.

Pope confronts Catherine and finds that she packed bags for herself and Lena to potentially run. After Catherine fails to convince him that she never planned to turn him and his family in to the cops, Pope smothers her with a pillow.

He takes her bags and buries them with her in the desert. And from that point on, it's believed by almost everyone that Catherine had skipped town and deserted Baz and Lena.