stephenville is not for me. natalie morales (voiceover): michael chose indiana, and susan made good on her ultimatum. she filed for divorce in february 1987. it was never finalized, but they didn't live together after that. five months later, susan was dead, and now detectives were combing through the evidence, looking for leads. they would find plenty. lester holt (voiceover): coming up. richard pringle: it was a chair. and beside that chair was a small table, and it had an ashtray with cigarette butts in it. lester holt (voiceover): a killer who made himself right at home. richard pringle: somebody had been sitting there smoking and watching tv. sitting there for a while. it just seemed like it was somebody that she knew. lester holt (voiceover): when "dateline" continues. some people just know they could save hundreds on car insurance by checking allstate first. like you know to check the weather first, before sailing. it's gonna get nasty later. yep. hey! perfect day for sailing, huh? have fun on land. i'll