This story was originally broadcast on Feb. 3, 2007.
In Dec. 2004, Jennifer Corbin's young sons found their mother dead with a gunshot wound. When a tipster later told police that Corbin's death might be connected to an apparent suicide 14 years earlier, investigators quickly re-opened the cases.
Correspondent Peter Van Sant reports on the investigation for 48 Hours Mystery.
Steve and Kelly Comeau met their neighbors, the Corbins, shortly after the family moved in across the street in 1999.
It turned out their new neighbors, Barton "Bart" Corbin and his wife Jennifer, were throwing a birthday party for their son, Dalton, on the same day Steve and Kelly were planning to celebrate their daughter's second birthday.
From then on, Stephanie Comeau and Dalton Corbin celebrated their birthdays together.
They lived in Buford, Ga., outside Atlanta, where Jennifer was a pre-school teacher; her husband Bart had his own dental practice.
The Corbins had a second child, Dillon, and the two families became inseparable. By 2004, after sharing the past five years with the Corbin family, the last thing the Comeaus could have imagined was living a life apart.
It was about 7:30 a.m. on Dec. 4th when Kelly Comeau heard banging on her front door; outside was Dalton Corbin in his pajamas.
Through tears, Dalton told Kelly that his mother was dead. "I just ran across the street," she remembers. "And I went in and could not believe what I had seen. The boys found her first. That was heartbreaking."
When Detective Marcus Head arrived at the Corbin's house, the officers told him it looked like a suicide. There were no signs of a struggle, papers were found by Jennifer's head that could be a suicide note, and there was a gun.
Bart was tracked down at his brother Bob's house, where he had spent the night. Bob broke the news to his brother. "And he basically broke down. Went up my stairs in my house and proceeded to throw up in the bathroom. Complete shock," he remembers.
Later that day, seven-year-old Dalton Corbin was interviewed by the police. "Do you have any idea why you think you're here today?" a detective asked the little boy.
"Cause my mom got killed this morning," Dalton replied.
Dalton told detectives that his parents had been arguing a lot that week. When asked if he thought his parents might divorce or separate, Dalton replied with an affirmative, "Mm-hmm."
By early evening, Det. Head had shifted his focus to the couple's troubled marriage and wanted to learn more about Bart and Jennifer Corbin.
It turned out Bart had an alibi for the night Jennifer died. Det. Head learned that Corbin had left the house around 10 p.m. to meet two of his friends for a late dinner and drinks at a local pub.
"And then he went from there and got coffee and went to his brother's house, about 20 minutes away from here," Head explains.
Police talked to Jennifer's family and friends to learn more about her. Det. Head says, "We're trying to find out if she made any remarks to co-workers or friends about recent troubles with Dr. Corbin."
That summer, Jennifer had told her family she wanted to leave Bart. "She said that she just had no emotion for him anymore. She said, 'You know, I love him because he's the father of my children, but I'm no longer in love with him," remembers Jennifer's sister Heather.
But by the fall, Jennifer had already fallen in love with a man she had met on the Internet. And although the two had yet to meet in person, they were planning a life together.
Bart didn't learn of his wife's relationship until just before she died, when he stumbled across some of her e-mails. He then filed for divorce.