a woman who feels she was cashiered, fired because of this younger woman and nobody gets away with that and i'm going to kill you? >> there's a lot to yolanda. there's a lot to yolanda. >> a lot of bad if you ask ramon santa cruz. >> i didn't like her from the beginning because she was very evasive. the apartment was always dirty. she was never a good person to begin with. >> detectives met with yolanda cerrillo, who freely admitted that she'd been devastated when michel dumped her. but she had no idea who beat his wife to death. >> she said she didn't know anything about it. >> but the detectives noted something else about yolanda. she lived just a few minutes from the parking lot where they'd found wendy. >> when you started adding up all the little things together, then her proximity to the crime scene, i'm very interested in yolanda cerrillo. >> no one knew what yolanda was hiding. that would come later. and so would the revelation of a motive that seemed to explain every violent little thing. >> coming up, a million reasons why someone wanted wendy dead.