But was it really an accident or was it something else? Karen Saffian, Dow's girlfriend of eight years, claims to know: "Dick Dow is getting away with murder," she says.
Saffian was a single mom just out of college when she first met Dow, two years after the fire. "He revealed to me that Janet and Steven, his wife and son, had died in a tragic accident," she says.
Saffian said Dow never talked about the accident until one night, five years into their relationship: "Just out of the blue, he just looked at me and said, 'How do you think Jan and Steven really died, Karen?'"
Saffian says Dow then told her what really happened back in December, 1982 - a story he never told police investigators.
According to Saffian, Dow said his stepson had used one of his police revolvers to kill Janet Dow. He then recounted how he had to kill Steven Dow with the axe. According to Saffian, he admitted the fire that killed his wife and stepson was no accident.
Saffian says Dow confessed to her, "'I put them both in the car. I rolled the car down the hill. I went back to the house and I waited for the police to come.'"
Saffian says he told her if she ever told anyone his story he would simply deny it. She kept his secret for four years, convinced that Dow had acted in self-defense.
But she started to have doubts when she began to see what she describes as violent behavior. "He would punch himself, he would hit himself,"says Saffian. "If you were watching it, you would cringe at every blow."
Fearing for her safety, she broke up with Dow and went to the police with her story in 1993. Eleven years after the crash, the state re-opened the case.
The state hired Thomas Bohan, an accident specialist, to taka second look at what happened that morning.
To recreate the accident and fire, Bohan and his team found a 1982 Saab - the car the Dows owned at the time - and re-created the crash. Bohan and his team rolled the car into the ditch, at the speed that he calculated it had traveled during the accident.
When the car reached the ditch, nothing happened. The gasoline in the back seat never ignited. In fact, says Bohan, "We only got it to ignite when a rag was thrust inside the vehicle and a window was left open to let air feed the fire."
Bohan now believes the fire was set from outside the car.
What are the odds of a such a low-speed accident knocking the Dows unconscious? "It's hard to put a numerical figure on it, but I think if you said never, you probably wouldn't be wrong in your lifetime," says Bohan.
He discovered something else in the official report: Police never found the carburetor Steven Dow supposedly placed in the back seat of the car.
The results of Bohan's tests devastated Wally Madeiros, who vowed to get justice.
But 11 years after the deaths, can the state build a strong enough case to prosecute Dow? Find out.
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