Yes, the relationship with the boyfriend was violent enough to
suspect the boyfriend had something to do with Dena's disappearance. But, when a thorough investigation into said suspect produced NO evidence whatsoever, Bertalotto should have been smart enough to figure out that he needed to find a new suspect. Lucky for Mark Keough, Dena's disappearance didn't get the national spotlight, or else he would have been wrongfully convicted. Instead, Dena's case just went into the cold file storage, and Bertalotto advanced to being a detective for the DA's office.
http://www.modbee.com/2011/06/28/1752930/jones-trial-former-detective-says.html#storylink=omni_popular
Be sure to read the comments -- especially the ones that call for an immediate lynching. That's exactly what people would have done with Keough -- just took him to the nearest tree and strung him up, no matter that he wasn't guilty. It's because of people like this that our justice system sucks.
Oh, and don't overlook zitalian's post -- s/he wants to punish Jones's parents, too.