"They would fight and then get back together again, while she hid everything to protect him," Tanya Brown says

Credit: Maury Phillips/WireImage; Ron Galella/WireImage

Watching certain parts of Big Little Lies was upsetting for Tanya Brown.

Like one of the characters on the hit HBO series, Brown’s sister, Nicole Brown Simpson, 35, endured an abusive marriage and relationship with her ex-husband, O.J. Simpson.

“When I watched the show, I thought, ‘Oh my God,’” Brown tells PEOPLE. “My sister lived that life. I had to pause the show several times while I was watching it because I thought, ‘Wow,’ this is my sister.”

Brown Simpson’s life ended with her murder 25 years ago today, on June 12, 1994, when she was fatally stabbed along with Ron Goldman, 25, a part-time model and waiter, in the tiny courtyard of her Brentwood, Calif., condo.

Nicole Brown Simpson, Ronald Goldman
Nicole Brown Simpson and Ron Goldman
| Credit: Frank Edwards/Fotos International/Getty; Lee Celano/WireImage

Five days later, O.J. was arrested for the double-homicide. He was acquitted of their murders in 1995.

Like Celeste of Big Little Lies, played by Nicole Kidman, and husband Perry, played by Alexander Skarsgard, “Nicole and O.J. had a hot love affair,” she says.

“They would fight and then get back together again, while she hid everything to protect him,” she says. “What I saw was the perfect depiction of what an abused woman goes through. I saw my sister in that relationship.”

During the trial, jurors heard her sister’s anguished 911 calls pleading for help.

Denise Brown, the sister of murder victim Nicole
Denise Brown, Nicole Brown Simpson’s sister, cries on the witness stand during the murder trial when a photo she took of her sister’s bruises in 1989 is shown.
| Credit: POO/AFP/Getty

“I didn’t listen to that in 25 years and I listened to it (recently) and heard the fear in my sister’s voice,” she says. “It was very hard.”

Domestic violence, she says, “affects everyone.”

Commemorating the 25th Anniversary of Nicole’s Death

On Wednesday, Brown and her mother, Juditha Brown, plan to light a candle in Nicole’s memory “and just be,” she says.

On Tuesday she went to the cemetery to visit Nicole’s gravesite. She left a white rose at the condo where her sister lost her life.

Others are invited to participate in an online candlelight vigil on FlockofAngels.org, she says.

While she thinks about Nicole every day, she says this anniversary “hit hard for some reason.”

“The silver anniversary has brought up so many memories.”

Gathering up pictures of Nicole, some of her sister’s favorite jeans and a dress and other items to the Alcatraz East Crime Museum for its exhibit honoring her sister, “Passion for Life: Nicole Brown Simpson,” made her relive a lot of moments she thought she had forgotten.

“Collecting the items, having to go through the photo albums and putting stories to the pictures evoked a lot of emotions,” she says.

She also visited the condo on S. Bundy Drive where her sister lost her life.

“All these memories came flooding back,” she says.

Those memories include going into Nicole’s condo shortly after the murders, not long after police had finished working the crime scene.

There she came upon the candles her sister had placed around the bathtub the night she died and the Ben and Jerry’s ice cream container one of the kids had left behind.

“Everything was covered in black finger dust,” she says.

“It was hard to be there,” she says.

Seeing the front steps and walkway was the hardest.

“I remember being there right after the murders and opening the front door and seeing Nicole and Ron’s blood,” she says. “There was blood everywhere. We had to clean it up. We had to hose it off – with hundreds of people standing out front and watching. I don’t have happy memories of Bundy.”

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O.J. Simpson, Nicole Brown Simpson and their children in March 1994.
| Credit: Barry King/WireImage

But she does have happy memories of her sister — and her zest for life.

“We had a lot of fun and the fun was created by her,” she says. “Nicole always wanted every event to be special and be a celebration. She always wanted to create memories.”

Brown continues to quietly live her life, spending time with her family and serving as a life coach and speaker.

She also wrote two books: 2014’s Finding Peace Amid the Chaos, which details the pain she experienced after her sister’s killing and the sensationalized trial that followed; and 2015’s The Seven Characters of Abuse.

She and her sister, Denise Brown, have devoted much of their lives to raising awareness about domestic violence and helping others.

One of the things Brown wants to stress is that anyone who feels troubled, or concerned that they may be in an abusive relationship, should seek help.

“I always say, ‘You’re not alone. Make that call and ask for help.’”

People’s special True Crime Stories edition, THE TRIAL OF O.J. SIMPSON, is on sale now at Amazon and wherever magazines are sold.