Believe it or not, Melanie says it was all over a simple dryer sheet. "He hated them. And I always left them in the pile of laundry," she says. "And from there the fight progresses to me getting slammed up against the doorway and getting the dyer sheet shoved in my mouth and slapped across the face."
"At this point one of the kids is there. And I grab him; scoop him up lock myself in the bathroom," she adds.
Asked what Bill was saying to her through the door, Melanie says, "'I'm gonna take the kids and you'll never see them again.'"
Melanie says Bill packed his bags and stormed off in his car. Two days later, she filed a restraining order, as Melanie says she feared Bill could pick up their kids and take off with them.
But Bill never tried to contact Melanie, their kids, or anyone else. He simply vanished. As days turned to weeks, Bill's sister Cindy questioned why Melanie hadn't filed a missing person's report.
"It wasn't that out of character for him to have a tantrum, pick up and be gone," Melanie explains.
Three and a half weeks later, with still no word from Bill, Melanie filed for divorce.
While Melanie was taking measures to end her marriage, Virginia Beach police were analyzing those matching suitcases found in the Chesapeake Bay. A fingerprint check confirmed the man inside the luggage was Bill.
But who killed him and how did his body end up more than 300 miles away from his home in New Jersey?
CSI investigator Beth Dunton quickly determined that Bill McGuire was shot in the head and torso with a .38 caliber gun. But other forensic evidence was far more difficult to come by. "The suitcases were saturated with water," Dunton explains. "It just destroyed a lot of the smoking gun type of evidence that probably was in the suitcase. The water became my greatest obstacle."
As investigators continued to search for clues, police informed Melanie her husband was dead. "I couldn't feel the ground under me. I was devastated," she tells Maher.
But there was one clue that caused investigators to question the grieving widow: the blanket found wrapped around Bill's torso was the very same kind of blanket used at the fertility clinic where Melanie worked.
Bill's sister Cindy refuses to believe that Bill had been violent with Melanie. "I know my brother. He would never lay a hand on a woman," she says.
Cindy says she never saw any emotional, physical or verbal abuse aimed at Melanie. "And anyone that knew Melanie knew that no one would get away with that. No one could do that to her," she says.
And Cindy insists Bill would never abandon his children.
Det. Pickell says Melanie reluctantly admitted those suitcases belonged to her and Bill. "We just felt that she was holding some information, a lot of information," Pickell says.
She hinted that her husband's trips to Atlantic City may have put him in contact with some shady characters. "She informed us that her husband liked to gamble. That her husband had a knack for pissing people off," Pickell tells "48 Hours."
Bill's car was found in Atlantic City. Even so, Pickell believed Melanie was misleading him. "When you have a husband that's missing but nobody's reported him missing...yeah, she immediately becomes a suspect," he says.
Police searched the McGuires' apartment, their storage unit and Melanie's car but found no murder weapon, or a tool used to cut up Bill's body. In fact, there was no evidence of a crime scene.
The investigation seemed stalled; police desperately needed more evidence. Working on the theory that Bill was most likely killed in his home state, police in Virginia handed off the case to New Jersey. There, the investigation would really zero in on the prime suspect, Melanie.
New Jersey State Police Detective David Dalrymple checked for weapons purchases, and quickly hit pay dirt: Melanie had purchased a Taurus .38 special revolver.