Nicole Brown Simpson's sisters recall shocking verdict: 'I couldn't scream, I was just numb'

When O.J. Simpson was found not guilty of the murders of his ex-wife Nicole Brown Simpson and Ron Goldman, Brown Simpson's sister Denise Brown was "in shock."

"I thought it was gonna be a hung jury," she told ABC News anchor Diane Sawyer.

"We were told by Judge [Lance] Ito, 'Nobody make a noise,'" Denise Brown said. "And then I heard [Ron Goldman's sister] Kim scream, and I just thought, 'Oh my God.' But I was in such shock, I couldn't scream. I was just numb."

Watch "Good Morning America" Wednesday at 7 a.m. ET for more from Diane Sawyer's interview with Nicole Brown Simpson's sisters: Denise, Dominique and Tanya.

Next month will mark the 30th anniversary of the murders of Brown Simpson, 35, and Goldman, 25. The two were brutally stabbed to death outside Brown Simpson's Los Angeles home on the night of June 12, 1994, as Brown Simpson's two young kids slept inside.

Simpson was arrested for the double murder and his "trial of the century" captivated the country. In 1995, Americans across the nation gathered around TVs to watch as the former NFL star was acquitted of all criminal charges.

But for Brown Simpson's sisters, witnessing history from inside the courtroom, the verdict was deeply personal. After the acquittal, the Browns returned home where Nicole Brown Simpson and O.J. Simpson's two young children, Sydney and Justin, were waiting.

The sisters said their mother instructed them to not show their grief to Sydney and Justin.

"She said, 'Put a smile on your face when we walk in the door,'" Denise Brown recalled. "'Whatever was best for them,' is what she would always say."

Today, Sydney and Justin are in their 30s, with families of their own.

The sisters said they don't talk to Sydney and Justin about their father.

"I don't know what kind of a relationship they had with him," Dominique Brown said. "I'm there to love on them, and I'm there to love on their children."

While Simpson always maintained his innocence in the killings, a civil jury in 1997 found him liable for wrongful death and he was ordered to pay $33.5 million to the Goldman and Brown families. Simpson died of cancer last month at the age of 76 -- without paying the lion's share of the civil judgment.

"We didn't get a penny, just to make it clear," Denise Brown said. "It was the estate of Nicole Brown Simpson for Sydney and Justin. ... It's always been about the kids, you know, and so it will continue to be about the kids."

As the Browns near the 30-year mark of the murders, a new Lifetime documentary has unearthed pictures and videos of the sister they loved so much.

"I love the videos. Because for me, the videos, I mean, as hard as it is to hear her speak and to see her moving ... I love seeing it, because she was just so graceful and elegant and just so sweet," Denise Brown said.

"It's the voice of Nicole that we wanted to hear. We want to have people hear it, we want to have people get to know her," Denise Brown said. "Because so many people said, 'We don't even know what she sounds like ... who is Nicole?'"

"So, I hope they get a true sense of who Nicole is in this documentary," Denise Brown said.

The new Lifetime documentary, "The Life & Murder of Nicole Brown Simpson," airs on June 1 and 2.

If you or a loved one are experiencing domestic violence, please call the National Domestic Violence Hotline at 1-800-799-7233, or access help through their chat at thehotline.org.