Stacey Burns was a popular figure in the lakeside community of Wolfeboro, N.H.
"Everybody went to her house," said Fae, a close friend of Stacey's. "The door was always open to everyone, old and young."
Her large colonial house sits on the main street of Wolfeboro, a tight-knit town with a population of 6,531 people that balloons to 25,000 during the summer when tourists flock to the picture-postcard New England town.
Watch "20/20" at tonight at 10 p.m. E.T. to see exclusive interviews with the men in Stacey Burns' life.
Stacey was a school nurse at Carpenter Elementary School in Wolfeboro. She met her husband Ed Burns more than 20 years ago when she was a student and he was a young merchant marine. Stacey's big brother, Michael Keane, recalls meeting Ed for the first time and thinking, "[He] was an interesting fellow -- a little eccentric."
After a whirlwind courtship, Stacey and Ed married and by their 10th anniversary, they had five children. As a merchant marine, Ed spent months at a time out at sea while Stacey stayed in Wolfeboro caring for their growing family. When Ed returned home from sea, tensions would arise between them.
"We both had to adjust because we were both commander of the ship, if you will. And I found out that even when I was home, I was actually second in command," Ed said.
Brittany, the Burns' live-in babysitter, witnessed the increasing strain on Stacey.
"It wasn't an ideal marriage for her," she said. "He wanted to know what Stacey was doing at all times. And if she would tell him the truth, he still wouldn't believe that it was the truth."
Eventually, Ed's desire to control Stacey became too much for her to endure, friends said, and she filed for divorce while Ed was out at sea. The news came as a shock to Ed Burns, and by Christmas 2008, Stacey and Ed were officially divorced.
Newly-single Stacey began dating a man whose son played hockey with her teenage son Michael.
Jim Vittum was a logger and divorced father of two children. He fell in love with Stacey soon after they began seeing each other.
"Three months into [the] friendship, I think we were in love," Vittum told "20/20."
But Stacey's babysitter says Stacey wasn't ready to start a serious relationship since she'd just been through a divorce.
"Stacey told me, '[Jim] thinks he's going to move in here, and we're going be like the big Brady Bunch.' And she's like, 'I am not ready for that,'" Tufts recalled.
Stacey's friend, Fae, remembered that "Jimmy had a hard time with Stacey saying, 'No. '"
On the morning of May 10, 2009, Mother's Day, Stacey and Jim were supposed to take their two daughters to a lacrosse tournament. Stacey and her daughter never showed up at the game, so Jim drove to their house.
The driveway was blocked by an ambulance, and Jim feared the worst.
"My first thought was, 'Maybe she had an accident and maybe she killed herself,'" he said.
Stacey's daughter broke the news to him, telling him, "Jim, mom's dead."
Burns had been stabbed multiple times during the early morning hours. Police surmise that an intruder entered the Burns' unlocked house while Stacey and the children were asleep. Her 15-year-old son discovered her body in her bedroom the next morning.
Burns' murder sent shockwaves through Wolfeboro.
"It really struck a terribly strong chord in the community," said Union Leader reporter Paula Tracy.
Burns' close friend Peggy was shocked when she heard the news.
"Whoever that creep is knew that those kids were sleeping in the house and they were going to find her on Mother's Day," she said.
Stacey's funeral mass was attended by more than 700 people. As friends and family mourned, New Hampshire police were left with the daunting task of figuring out who would want to kill a beloved mother of five young children.
The police interviewed those closest to Stacey, including her ex-husband, Ed Burns and her friend Jim Vittum.
Surprisingly, Jim Vittum had approached the police that morning insisting, "'You've definitely gotta look at me. You've gotta clear me 'cause I'm gonna be his reasonable doubt. Eddie killed her.'"
Ed Burns denies Vittum's accusation.
"The way to answer that is an old cliche," Ed Burns said, "When you point your finger at someone, there's three fingers pointing back at you."
Interviews with Stacey's friends and family about the days leading up to her murder reveal that she had seen her ex-husband Ed two days prior to her death. She met him to hand off their three youngest daughters for the weekend.
Sister-in-law Andrea said Stacey was nervous because she was due to meet Ed in court the following Monday for a contempt of court hearing related to a money dispute stemming from their divorce.
"I'm sure she wasn't looking forward to it," Andrea said.
That evening Stacey went out to dinner with a local man. That dinner led to a confrontation between her date and Jim Vittum who -- despite having broken up with Stacey -- was waiting outside her house that night. Vittum said he thought she shouldn't be dating anyone at that point.
"I wanted to confront the two of them so that I could ask her, 'What are you doing?'" Jim Vittum said. "You could say I was stalking her, but I think I was being her friend."
Jim said they had broken up weeks before, but her friends said, the following day, Stacey felt she had to make it clear to Jim -- once and for all -- that they were through.
"Stacey had decided to go see Jim that afternoon and to break it off," Moore said, "And I know that she did."
Nevertheless, Vittum showed up at Stacey's house that same night to watch a movie with Stacey and her teenage children who were having a sleepover with friends. Jim said he was there at Stacey's invitation. He also said that he left Stacey's house around 11 that night, a detail her friends said was confirmed by Stacey's children.
The following morning Stacey was dead.
More than a year-and-a-half later no arrest has been made in the murder of Stacey Burns. Law enforcement officials in New Hampshire have declined to comment, citing the ongoing nature of their investigation.
Both men said they had nothing to do with Stacey's murder. Ed Burns said he was at a party in Boston the night of her murder -- an account backed up by a friend who had video to prove it. Jim Vittum's ex-wife said he was at her home chaperoning a teenage sleepover the night of the murder.
Stacey's family is left to wait and wonder what, if anything, they could have done to save her.
"This is a real cautionary tale," said Stacey's brother Michael, "about looking for signs and identifying the things you don't like. My sister deserved a long, happy life and she's not going to get it because someone was very selfish, and they were going to take her from this earth. And I can't imagine how anyone could go that far."
Stacey's five children are being cared for by their father Ed. The family has faced extreme financial hardship and the threat of foreclosure has forced the family to move away from their longtime home, leaving their memories behind.
To provide tips on the Stacey Burns murder investigation, call the New Hampshire State Police tip line at 603-223-3856 or Wolfeboro Police at 603-569-8173.
Watch the full story tonight on "20/20" at 10 p.m. E.T.