Ten years ago, on Halloween night in 2009, 38-year-old Nori Amaya and her brother, Carlos, shared a bottle of their favorite wine as they closed their restaurant for the evening.

Nori and Carlos, who was only a few years younger than his sister, told Dateline the two siblings had a close bond. Carlos said they were close all through grade school and at Montgomery college in Maryland, which they both attended.

Carlos opened the Italian restaurant Coppi’s Organic in Washington, D.C. and Nori eventually joined him as a business partner.

Halloween night 2009 was a Saturday and Nori, a self-proclaimed salsa queen, had plans to go out dancing. She was dressed in all black except for a brightly-colored peacock mask her brother had helped fashion out of a Venetian mask.

It was the last time Carlos would see his sister alive.

“Ten years. That Halloween was the last time I saw my sister. Talked to my sister,” Carlos said. “And I never got to see her or talk to her again.”

Carlos told Dateline Nori went to the Rumba Cafe on 18th street where she had been dating the owner, before heading to the Russia House and then to Bravo Bravo for dancing.

"There was talk that she had visited a couple of locations and maybe parties, etc., on that day,” Metropolitan Police Captain Anthony Haythe told NBC Washington.

Carlos told Dateline Nori “called me at some point that night and asked where I was. I told her I was at a friend’s party, but it was boring and that I was leaving soon, so there was no point in her coming out.”

That phone conversation was the last time Carlos spoke to Nori.

Nori grabbed a cab and made it home around 2:30 a.m. According to NBC Washington, security camera footage shows her walking into her apartment building in the 3600 block of 16th Street NW at that time.

“I always wonder what would have happened if I just told her to come out,” Carlos said. “Would she be OK now? Would she be alive?”

A day passed and Carlos didn’t hear from his sister.

“It’s not like her. We’re very close,” Carlos said. “But I wasn’t really worried at that point. She was having some issues with the guy she was dating and I figured she just needed her alone time.”

That day a cab driver called Nori’s mom to tell her Nori had left her cell phone in the cab Saturday night.

Carlos said it wasn’t unusual for Nori to leave her phone places. He picked it up and held on to it because he had to get to work at the restaurant and Nori was supposed to come in for work that evening. But she never showed up.

On Monday, November 2, when Nori didn’t show up for a catering event they had planned, Carlos started to worry.

He told Dateline he went to her 11th floor apartment at the Woodner on Monday morning, but no one answered the door. Carlos said he just figured she was sleeping, so he left. But he came back later that evening, this time with his younger sister, Blanca, and building security.

That’s when they made the gruesome discovery.

Nori was in her bed, in her underwear and wrapped in the bed sheets. She had been strangled, police said.

“I pulled the bed sheets back and I saw she was blue… just blue,” Carlos told Dateline. “I started screaming, ‘Wake up, Nori! Wake up!’ I tried to revive her, I tried to bring her back to life. But she was dead.”

While investigating the scene, detectives said they discovered that all of Nori’s fingernails had been removed, apparently in an attempt to keep the police from getting any DNA, according to police.

“There was definitely a struggle. You could tell,” Carlos said. “She fought for her life.”

Police recovered male DNA from the scene, but have not made a match. No suspects have been named in the case.

“To this point we still have not gotten enough information to reach the point of making an arrest in this case,” Capt. Haythe told NBC Washington.

Carlos told Dateline he believes the killer is someone Nori knew.

“The scariest part is that the murderer is still out there. And he could kill again, if he hasn’t already,” Carlos said. “The police have unidentified male DNA, and we still don’t have him 10 years later. It’s frustrating. And heartbreaking.”

Before the murder, Carlos said their family faced their share of hardship.

Carlos, his sisters and his mother, immigrated to the United States from El Salvador, when he was just a toddler, and he said all they wanted was to live the American dream.

But it wasn’t easy.

When Nori was in her early 20s, Carlos said she was diagnosed with brain cancer and underwent two surgeries. Her recovery took years.

“We survived wars in our home country and then Nori battled brain cancer,” Carlos told Dateline. “She survived -- only for her to be brutally murdered like this.”

Carlos told Dateline that as the years pass, he worries the investigation is losing steam and that his sister’s killer will never be found.

“I remember every horrific detail of finding her that night. It’s something that’ll stay with me forever,” Carlos said. “But it’s a reminder to never give up finding this guy. I don’t know where to go or what to do next, but I’m not giving up.”

Metropolitan Police told Dateline they are continuing to investigate Nori’s case.

If you have information about Nori’s case, call the Metropolitan Police Department at (202) 645-9600 or text a tip to police at 50411.