cara rintala would be tried a third time for the murder of her wife ann.ut first, cara had a heart-to-heart talk with brianna, now 9 years old. >> she told her a lot. and she says -- >> that some people -- >> mom, i already knew. >> she says, "some people think i did something bad, something terrible. but i just want you to know that it's not true." >> reporter: in september, 2016, trial number three opened here at hampshire superior court in northampton, mass. prosecutors steve gagne and jen suhl returned with a streamlined argument. >> we were caught sort of in this trap of being responsive to the defense and we decided let's play offense. >> reporter: in trial number two, they'd put the possibles, mark oleksak and carla daniele, on the stand, only to knock them down as viable suspects. perhaps, they reasoned, they had confused jurors. so this time, they were gone. and now they focused on cara, and the helpless victim who fell down those stairs. the wife who was strangled, they said, for as long as four minutes, until she died. >> her last precious breat