prosecutors stephanie paulissen and scott simpson laid out the case for the jury. >> we understand why angry. but that's not justification to go attempt to run down your husband's mistress and kill him in the process. >> reporter: the star witness for the prosecution, bonnie contreras. >> i start to get hit from behind. >> reporter: bonnie told the jury how she watched with horror as she believed frances deliberately knocked bill off the road. >> i see her hit bill with the truck. and i see him fly off the motorcycle. >> reporter: bonnie said she later discovered frances' daughter, nikki hall, had left a message on her voice mail during the car chase. a message that seemed to speak to frances's intent that evening. >> told you to watch your back you [ bleep ] stupid slut. >> what does that tell you? that they were out to cause harm to somebody. >> this is not an accident. >> reporter: tim lovett was the state's collision reconstruction expert. he said the evidence showed frances chased and hit bonnie. >> that escalade definitely hit that range rover at least two, maybe three times. >>