liz sevilla volunteered that lars the contractor was slow to finish projects around the house. >> she did send me a picture of what lars did in the bathroom and the measurements were incorrect. and so it ended up making a hole. hole. >> reporter: debbie's friend ellen mitchell noticed a change in debbie's behavior when she returned home from business trips. >> she would come home from some of these trips and say, hey, let's go get a drink, let's have some dinner. >> she was not the kind to stay home and bake cookies or walk in the door and serve you a meal, because she'd worked just as hard, too. >> and all these friends, she goes and spends tennis time, does things -- maybe just -- you feel like you're gettin' shortchanged. >> he wanted more of debbie? >> right. >> he did want more from debbie. >> reporter: all marriages have problems. very few end this badly. so investigators decided to take an even closer look at the husband who pulled the trigger. >> coming up, lars seemed upset. was he? here's your buick sir. actually, that's my buick. your buick doesn't have a roof rack! this is