narrator: luckily, scott purk and his family escaped unharmed. woke up around 3:00 in the morning to go to the bathroom, and that's when he discovered the fire. he alerted everyone, and they were able to get kids out of the house. narrator: veteran arson investigators soon realized why the house went up so fast. there was a trail of gas that was poured. you could see the pour pattern on the grass leading all the way to the house and around the foundation. narrator: since detective ken mifflin assumed he was dealing with an arson fire, he asked scott purk the obvious question -- "was there anyone who would want to harm him or his family?" and scott immediately volunteered a possibility. scott and his wife had an open relationship. they were swingers, and they had an interesting lifestyle, to say the least. mifflin: they openly date, even long-term-dating the same people within the marriage, and they're both comfortable with that. they both have their own girlfriends and boyfriends and so forth. narrator: was it possible a boyfriend or a girlfriend

walsh: scott purk was taking a bath, and he saw his wife walk past the door a couple of times.etcalf: but the first thought was, "why would she do this, this close?" you know, she was within like two weeks of having the baby. so, you know, it just -- it really didn't make a whole lot of sense. narrator: everyone was shocked. what happened seemed so impulsive, especially with a baby on the way. even first responders and akron police were suspicious.