By now everybody knows her name. But little is known about Brooke Mueller, who filed a temporary restraining order against her soon to be ex-husband, Charlie Sheen, on Wednesday and entered into a vicious custody battle over their 2-year-old twin boys.

Mueller’s 10-page declaration included in the court documents was a bombshell, revealing a battery of cruel insults and claiming the actor had threatened to behead her, saying: “I will cut your head off, put it in a box, and send it to your mom!”

The latest skirmish with Sheen has put the media glare again on Mueller, who just a few years ago was all but unknown in Hollywood and who, unlike Sheen’s former wife Denise Richards, is not a celebrity. In an exclusive interview with The Daily Beast, her brother, Scott Allen Mueller, 35, described Brooke, 33, as a gregarious person with a competitive streak.

Despite their differences—Brooke has been struggling with sobriety, while Scott said he has never smoked a cigarette or been drunk—the two have a tight bond, he said. “We’re closer now than ever before,” he said. “She needs the kind of unqualified love family provides given all the drama she’s endured.”

The Muellers grew up in upstate New York and as middle schoolers would play for hours in the woods, riding in the fields behind their house on a couple of four-wheelers their father had bought for them. Allen Mueller worked, at various times, as “a Miami and Key West police officer, a high school teacher, a real-estate broker, and even a part-time minister,” said Scott.

Two years after their father died, their mother, Moira Fiore, married Kenny Wolofsky, a millionaire who had made his fortune in the construction business.

Scott described his mother’s remarriage as “fairly traumatic for me. I was extraordinarily close with my father—Brooke was too. He was an incredibly charismatic guy.”

Wolofsky was well-liked, said Joe Lambiet, who chronicles Palm Beach’s social scene for his column Palm2Live.com. “He was very a popular person on the society scene, even though he didn’t go out as much as [Moira] did,” he said.

“My mom’s pretty good at picking husbands,” said Scott. “Kenny was an amazing person and continued to look after us and treat us like his own kids, despite my indifference and Brooke’s growing wild behavior. Eventually everybody around Kenny [grew] to love him.”

“I certainly knew about his past,” Brooke’s brother said of first meeting Sheen. “However, he showed himself to be generous, charming, and intelligent.”

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Brooke became a cheerleader at the exclusive Benjamin School, where tuition for high-school students is $23,000 a year. Mueller later tried acting, real estate, and even had a stint as a special correspondent on Extra.

But Mueller's teen years were full of trouble. She was arrested for a DUI when she was pulled over for running into a road sign. In 2001, she was arrested for cocaine possession. (The charges in both cases were dismissed.)

Said Lambiet: “She was a party girl—that’s not a secret. It doesn’t make her a bad person. She’s not atypical of the rich youth of Palm Beach. This is a town where the rich and famous come to party.”

Indeed, the social season in Palm Beach is a busy one, with a black-tie gala every night through spring. Moira and current husband Jon Fiore are regulars.

Scott Mueller said he suspected that Brooke’s new love was putting on an act. “I certainly knew about his past,” he said. “However, he showed himself to be generous, charming, and intelligent.”

Sheen’s charisma was obvious, Scott said: “The beginning of our relationship started off very well and I could see why my sister had fallen in love with him.”

If she had been living the luxe life in her late teens, Brooke’s life really changed when she met Sheen, whom she was introduced to by her friend Rebecca Gayheart at a party. The two stepped out as a couple at the Sixth Annual Chrysalis Ball in June 2006, working the red carpet like they had been doing it together forever.

They were engaged the next year.

In the beginning, the relationship seemed like a fairy tale. They were married in Beverly Hill Park on May 30, 2008, at the home of friends Paul and Adrienne Maloof Nassif, whose backyard was decorated to resemble an enchanted garden. An abundance of celebrities were in attendance, including Gayheart and husband Eric Dane.

The bride wore a dress by Reem Acra and a $500,000 rock on her finger; the groom splurged on a Men’s Wearhouse suit. They traded vows that were cozy and cute. OK Magazine reported that Sheen promised to “organize less and listen more,” “quit breaking a hug too soon,” and “mute the ball game when Brooke said, this is a matter of life and death.” Brooke, meanwhile, vowed to “cook more meals outside of the microwave,” “keep the pile of debris on my side of the bed below the two foot mark,” and “clean my closet at least once per decade.”

Things seemed to be going swimmingly. Brooke was pregnant by August 2008 with the twins, Max and Bob. Then came the big bust-up of Christmas 2009, when Sheen was charged with domestic violence. After a long, rowdy evening arguing in Aspen, Colorado, the couple’s fighting escalated in the morning, when he allegedly held a knife to her throat. Although Sheen pleaded guilty, served 30 days in rehab and probation, and had to sit through 36 hours of anger-management counseling, it appears that he has not changed much. The couple filed for divorce last year, but they will not be legally single until May 2.

Sheen and his camp have denied the allegations in Brooke’s most recent declaration. “Please be advised that Mr. Sheen has previously and continues to deny Ms. Mueller’s allegations of violence and death threats,” his attorney Mark P. Gross said in a statement provided to The Daily Beast. “Mr. Sheen clearly and coherently denied those allegations in his interview with the Today show Wednesday morning.”

Gross said the verbal agreement over custody that Sheen had tweeted about earlier was still up in the air. “Unfortunately, it is unclear as to whether that verbal understanding will be reduced to writing and signed by the parties,” he said. As for the kids at the center of the controversy? Said Scott Mueller: “The kids are wonderful. I’m sure they’re oblivious at this stage. I haven’t seen Charlie’s daughters [with Denise Richards] in a while, but they are really great kids and they had to go through some of the same drama, too. So it doesn’t seem like these negative things are adversely affecting the kids.”

Although her publicist said Brooke was unavailable to comment for this article, her declaration offers insight to her puzzling recent relations with Sheen. She was rumored to be living with Sheen and his coterie of women, a grotesque collection of porn stars and would-be models, and had even gone along with him on a trip to the Bahamas, despite their high-profile discord.

Until January, she had barely spoken or seen her husband since the Aspen incident, and she said he hadn’t sought out time with the children. But because Sheen had stated that he was sober, Brooke said in the declaration, “I made a big mistake and moved the children and myself temporarily in with” Sheen. She only attended the trip to the Bahamas, she said, because “I was afraid I would enrage Petitioner if I did not go. I wanted a new home for the boys and I was trying my best to continue to keep Petitioner happy.”

In her statement, Brooke is forthcoming about her own shortcomings, acknowledging that she had slipped in her sobriety—she has been to rehab in the past—and saying that after the Bahamas trip, she renewed her efforts and is in day treatment and traveling with a “sober companion.”

Her brother said she frequently injects humor into tough situations. That skill, no doubt, will come in handy during her next foray into the public eye, this spring, when she becomes a reality-TV star. Brooke will be one of four women featured in an upcoming show on the Oxygen Network centered around Paris Hilton and her closest friends. Although sources say the Mueller-Sheen drama is not being filmed, the exposure could serve to make Brooke an even bigger name.

But only time will tell if the cheerleader from Palm Beach with movie-star looks can get her groove—and her children—back.

Said Scott of his sister: “Like any brother, I purely hope she’s as happy as possible. Max and Bob will likely play a big role in that goal.”

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Tricia Romano is an award-winning writer who has written about pop culture, style, and celebrity for The New York Times, the Village Voice, Spin, and Radar magazine. She won Best Feature at the Newswomen’s Club of New York Front Page Award for her Village Voice cover story, about sober DJs and promoters in the nightlife industry, " The Sober Bunch."