he wanted to make better of his life. >> on november 20, 2008, 911 received a frantic call from cindy karlsen. >> 911. what's the location of your emergency? >> yes, i live at 885 yale farm road. >> okay. >> i think i need an ambulance. >> levi had come to the home of cindy and karl karlsen at the request of karl. >> karl told me that levi was going to come out to work on an old farm truck that we had that day. our plan was that we needed to attend my aunt's funeral. >> while levi is in the garage working under that farm truck, karl and cindy are getting ready and dressed to go to a funeral. >> i went and got in the passenger seat of the car, and karl had told me that, i'm just going to go out and let levi know that we're leaving. >> it was just a minute or two. and then karl came and got in the car. nothing seemed out of the ordinary. >> he and cindy leave to go to a funeral down in penn yan, new york. >> we were gone for, um, four hours. >> they return home. cindy first notices levi's car still parked in their driveway. she's kind of concerned. >> i went in the house and karl came up to the

we choose to reach out to cindy karlsen to further an investigation. >> that's when we started working kicks into high gear. police set up undercover officers and cindy agrees to wear a wire to meet with karl to try and elicit a confession. >> so right now i need to -- >> i know, but i'm just telling you -- >> i'm going to -- >> no. >> you just had to pump it? >> because it's so wobbly, you know. because the only thing that was touching the ground was just the back two wheels. >> any dessert? >> no. >> i'll have more coffee, thank you. >> sure. so then what happened? >> then -- >> what, did he make a noise? >> i mean, you'd think. >> it's not clear cut, it's not definitive. >> by no means did we think this was a slam dunk. >> at that point, we knew we were going to be bringing him in for an interview. >> investigators questioning karl for hours about his son levi's death. >> did you tell cindy, when she asked you if you pushed the car over on levi, did you push hard, do you remember telling her, it pushed easy? >> i don't remember ever -- >> could you have said that? >> if it is, then