Photo by Graham Cullen Frannie Sherwood, center, mother of Marijke McMahon, discusses how her eldest daughter became entangled in an abusive relationship which ended with Marijke's husband, Sean McMahon, murdering his wife and then killing himself. Also pictured is Natalie Morris, Marijke's sister, right, and cousin, Lauren Rose. VIDEO: Loved ones reflect on Marijke McMahon

Here, stacks of books were piled on the floor. Growing up, her sister was always reading 10 books at a time.

Standing in the new apartment, Natalie felt like her sister was finally free. The mother of twins was on her own, teaching, and working on a second master's degree.

"I said 'You're finally yourself, and I felt like for the past eight years, I haven't had my sister,'" Natalie said. "'My sister's finally back.'"

It has been more than six months since Marijke's murder.

On Oct. 25, Sean killed Marijke before hanging himself and setting fire to their Lake Linganore townhouse. Sean was 30. Marijke was 26. Today, neighbors describe the hole as a scar on the neighborhood. The twins, now 4, are living with family members as courts determine custody.

Looking back

Marijke's mother, Frannie Sherwood, who once lived two doors down, has moved away. Her daughter didn't discuss the problems in her relationship with Sean, but Sherwood said she now recognizes warning signs.

"Especially when I look back in retrospect, I can see the isolation and I can see the control," she said. "... He wanted us all at arm's length. He wanted her all to himself."

Sherwood remembered hearing Sean's story of how he met Marijke. It was the summer before her senior year of high school, when she was 17. He was 22.

Sean would go to Jimmy Cone, where Marijke worked, to get ice cream. One day, he finally got her to wait on him.

Marijke was that person everyone wanted to know, Morris said.

"She walked into a room and she lit up the room," she said. "And she was just so charismatic and had this aura about her."

Valedictorian of Linganore High School's class of 1999, Marijke was smart and motivated, Sherwood said.

She remembered her firstborn as strong-willed, and always busy doing something. Marijke had a million friends, Sherwood said.

Attempts to contact Sean's family were unsuccessful.

Sean showered Marijke with attention and gifts, spending nearly $1,500 on clothes for their first Christmas together.

Her sister was swept off her feet, Morris said. The couple "kind of became one," she said, ceasing to be individuals outside of the relationship.

"I think anyone who would date Marijke would be like 'Wow, you know, I'm the luckiest guy in the world to have a girl like this,'" Morris said. "... And I think it almost turned into an infatuation, almost, in the relationship."

Normally outgoing, Marijke changed, Morris said.

"I watched my sister be morphed into a different person when she was with him. It wasn't my sister," she said. "... (There was) an unsettled feeling in her that I sensed when she was in his presence, and I just knew that something wasn't right there."

Sean treated Marijke well, but Sherwood believed he was taking her away.

After graduation, Marijke planned to earn a degree at Shepherd University in Shepherdstown, W.Va., on full scholarship.

Then, the night before Marijke moved, Sean proposed.

Her family was supportive, but cautioned Marijke to slow down. Initially, the couple was going to wait to marry. Then, on Valentine's Day, 2000, Marijke called her parents on the way to the courthouse to tell them she and Sean were getting married.

In the months before her murder, Marijke confided in her mother that she felt pressured to marry.

"She had said to him 'You know my mother and father really don't want me to get married right now. Can we wait?'" Sherwood said. "And he got furious with her."

A time of isolation

In Sheperdstown, Marijke and Sean lived together until summer 2001. For a brief time, Marijke left, moving in with her mother. On her 21st birthday, Aug. 30, Marijke decided to go back to Sean, Morris said.

"(She) just did it and was almost kind of embarrassed about leaving and then going back, and didn't want to really talk about it," she said.

When Marijke became pregnant in fall 2003, she and Sean looked to Sherwood, a real estate agent, for help finding a house. With a limited budget, they couldn't find one they liked. When a house came up for sale on Sherwood's street, Sean suggested Sherwood sell them her townhouse and move to the neighboring end unit.

In 2004, Marijke gave birth to twin girls. In what should have been an intimate time between a mother and daughter, Sherwood said her daughter was isolated.

"He was very much a wedge between Marijke and I, and I couldn't get close," she said. "And again, I wanted to respect the fact they wanted to have this close family unit."

Marijke was soon back to work as a preschool teacher at the Butler School in Darnestown. After getting home from work, she would often invite Sherwood over. When Sean got home from his job at an information technology firm in Frederick, the whole air changed and she felt she had to leave, Sherwood said.

The couple rarely attended family get-togethers -- or would come only to leave moments later. Marijke would make excuses, saying Sean felt uncomfortable in large groups.

Before her murder, Marijke would tell Sherwood, "Mom, it's not that he tells me I can't go, but he makes my life so miserable that I don't want to go."

Lauren Rose, Marijke's cousin, said the family noticed a change in Marijke's behavior, but knew Marijke had a good head on her shoulders, so they kept it to themselves.

Rose said Sean respected the institution of marriage, but believed the man should be in control.

"But Marijke, like most young women -- that's not how you're going to live," she said.

Marijke had earned a master's degree in education from Loyola College in Baltimore, taking a year off to have the twins. She started a second master's degree in reading specialization and hoped to earn a doctorate.

As Marijke matured and the girls grew older, Sherwood said, Sean began to lose control.

"Marijke was changing and she was going to get her master's degree, and as he began to lose control, he couldn't handle it," she said. "And then the final blow was her leaving. He was very much a victim, he was a victim."

Over the summer, Marijke started to realize she wasn't happy. The couple attended therapy, but the relationship deteriorated. In August, Sherwood said Sean began locking Marijke out of the house.

Ultimately Marijke filed for divorce, the couple worked out a schedule to see the girls and she moved into the Market Street apartment.

Police later found e-mail exchanges indicating Marijke had started seeing someone. After Sean confronted him, it looked like the relationship was ending.

Her mother remembers Marijke in those days as caring for Sean and not embittered.

"She cried and she told me about a week before he murdered her, 'You know I don't miss Sean, I don't miss him at all. I miss our little family that we had. And I don't want to hurt him -- it's the last thing I want to do is hurt him, but I don't want to be married to him anymore," Sherwood said.

The fatal night

On Oct. 25, 2007, Sean McMahon prepared a will.

He took his 3-year-old twin daughters to his parents' house in the afternoon. He told them he was going to his job in downtown Frederick, but officers with the Frederick County Sheriff's Office determined he left work about 2 p.m. and never returned.

That evening, he called his parents, saying he was tied up at work. He asked if the girls were OK.

Police determined Sean and Marijke had arranged to meet that evening at their home. Sherwood speculates they met to talk about divorce papers, which Marijke had filed earlier in the month. Her daughter may have believed the twins were asleep in bed when she stopped by that evening.

She spoke with her daughter that morning, and Marijke told her she was planning on going to the Great Pumpkin Patch event with Sean and their daughters the following weekend.

Sherwood told Marijke she needed to keep her distance and stay safe. Marijke told her it would make Sean feel better: "Mom, it will be OK, he would never do anything to hurt me if the girls are there."

Later that night, shortly after Marijke arrived at their house, Sean bound and gagged her with duct tape before hitting her over the head with a baseball bat.

Police later found the charred bat near her body. They also found the body of a dog beside her.

Marijke died of a combination of head trauma and asphyxiation. With duct tape covering her mouth and blood filling her nose, she couldn't breathe.

After the murder, Sean doused her body and the house with gasoline.

Sean started the fire and hanged himself with a leather belt.

At roughly 8:30 p.m., neighbors heard a sound like thunder and felt their houses shake. They went outside and saw the McMahon house engulfed in flames.

It would be hours before firefighters could contain the blaze. Today, neighbors on either side still have not returned to their homes.

A new perspective

Since her sister's death, Morris said she has been on a quest to learn more about the warning signs of domestic violence.

"I have to step back sometimes because I'll read something and I'll go 'Wow. If I had this information before, would this have changed something?'" she said.

Morris listed the red flags -- the way Sean called Marijke names and criticized the way she looked. The way he threw her things as her family helped Marijke move out in early October.

The way he made her feel guilty about being away from the girls during his visitation time with them after they had separated.

Even during the time they were separated, Morris said, Sean still wanted to know everything she was doing. If she had a class, he would ask if she was coming straight home or going out with friends. In the weeks before the fire, he showed up at her work and hair appointments. Sherwood said he hacked into her e-mail and cell phone voicemail, calling every male in the contact list.

Three weeks before her sister's murder, Morris was with Marijke when Sean kept calling.

Finally Marijke picked up the phone -- he called to tell her he had their three cats put down. It gave Morris chills.

"The cats, to my sister, were like her children, and I just remember saying 'Marijke, oh my goodness. Why would he do that?' And her face went white and she was like 'I don't know.'"

Because Marijke was a teacher, her family believes she would have liked them to use her story to educate others.

Her story is one piece of the puzzle, Rose said.

"It does put a face with this epidemic," she said. "But there's so much good information out there that I don't think is making it where it needs to make it."

After her cousin's death, Rose prayed every day.

"After the prayer, I would be filled with all these thoughts, and I knew they were coming from Marijke. And they were never angry," she remembered. "'If you're that upset that I'm gone and how I was taken, then reach out and help people, and especially protect my daughters.'"

Through her work at MedStar Health, Rose met community outreach coordinators, who asked if Marijke's mother would be willing to tell her story.

Since then, the family began creating a documentary about domestic violence. In April, Sherwood spoke to students at Kenwood High School in Essex. She hopes to teach teenagers about healthy relationships.

"I would tell them to love themselves and take care of their own safety first before they were concerned and tried to help another person with their problems," Sherwood said. "Because I think that's what Marijke did."