(CBS) Garrett Wilson and Missy Anastasi didn't exactly have a marriage made in heaven. Wed in 1986, they lost an infant son the following year.

Anastasi suspected her husband may have had a hand in the child's death. But when the medical examiner ruled that the baby had died from Sudden Infant Death Syndrome, she put her suspicions aside and decided to stay with Wilson.

But the marriage wasn't easy. With Wilson, a charismatic Harold Hill-type character who sold musical instruments for a living, moving around the country, from one sales job to another, they were apart for months at a time.

Then in 1993, Anastasi discovered that her husband had secretly filed for divorce. Wilson later told her that he regretted having divorced her, and wanted to give their relationship a second chance. A year later, she agreed to join him in Texas, where he had found a high-paying job.

A few weeks before the move, Anastasi got a call from Vicky Wampler.

"I wanted to call, and say ‘It’s time to move on,’" says Wampler, who is Wilson's fourth wife.

Earlier that year, Wilson had married Wampler, and they had settled into a comfortable life just outside Dallas with their then 10-month-old daughter, Marysa.

Anastasi was devastated. It was then she realized that Wilson was capable of anything.

When Wilson called her to explain his new marriage, she accused him of murdering their son.

"I said, ‘Garrett, now that I see what you’re capable of doing to me, I know you killed my baby,’ and he said, ‘ Missy, you’d be dead if you were here.’"

Anastasi went to the police and told them of her suspicions. Although the case was very cold, she was determined to push it forward. She spent the next four years, writing hundreds of letters to countless officials, asking for help.

"If Garrett Wilson had never left Missy, this never would have come forward before, because she had - lock, stock, and barrel - believed in him," says prosecutor Doug Gansler, who led the case against Wilson. Details of that case are in "While Innocents Slept," a true-crime book by writerAdrian Havill.

Anastasi even warned Wampler to protect her daughter.

"He’s just not capable of hurting a child," says Wampler, who believes that Anastasi is motivated, not by justice, but by a desire for revenge.

"This type of relationship had gone on for years. He moved, and she followed pursuit. When she realized that he wasn’t coming back to her, I think that she became obsessed with his destruction."

Liz Bahlmann, another woman with whom Wilson had a relationship, agrees.

"She (Anastasi) would go to the ends of the earth and spend her entire life until she destroys him," says Bahlmann, She encountered Anastasi in 1985, before Wilson was married to her.

That summer, nastasi caught Bahlmann and Wilson on a date at a Delaware beach. Both women then discovered that Wilson had also been dating the other. Anastasi was enraged, Bahlmann says, and hit Wilson with her sandals.

Wilson and Bahlmann left the beach in separate cars. Bahlmann says Anastasi chased them in her car. "It was very frightening," she says. She says that she went off onto the shoulder; Anastasi denies this.

That day, Wilson told Bahlmann that he had intended to end their relationship and be with Anastasi. But by the end of the day he had changed his mind.

A few months later, he proposed to Bahlmann. But shortly after their wedding invitations went out, Bahlmann discovered that he had already married Anastasi.

"It was devastating, it was painful," says Bahlmann, who in her last conversation with Wilson told him that she wanted the $3,000 she had lent him. Wilson paid off the money soon after his son died.

How did Wilson cast his spell over so many women? He was charismatic and caring, says Bahlmann: "He treated you like a queen- like you were the only person on earth that mattered."

But despite her bad breakup with him, Bahlmann says that Wilson is not capable of
murder.

"Garrett Wilson is a con artist. he is motivated by greed, and the vehicle to get his greed is women," says Gansler. "He would certainly prey on a particular type of woman- a needy woman, someone who would be sort of taken in by him."

Can police gather enough evidence? Find out:

Part III