>> reporter: "i will kill you." the words of a man who looked guilty at every turn, said the prosecutor. of course the evidence was circumstantial, disputed. but there was one more player waiting in the wings. and what a story he would tell. coming up -- that tale would lead investigators back to the frasch house and a dramatic discovery. >> bingo. >> yeah, bingo. i literally looked at it for a minute. i was, like, seriously? >> when "dateline" continues. betty is saving big, holiday shopping at amazon. so now, she's free to become ... bear hug betty. settle in kids, you'll be there a while. ooo, where you going? facing expensive vitamin c creams with dull results? olay brightens it up with new olay vitamin c.while.