(KTLA) — The search is underway for a Southern California woman who disappeared while on a yoga retreat in Guatemala.

The missing woman, Nancy Ng, 29, from Monterey Park, disappeared on Oct. 19 at a retreat in Lake Atitlán, according to her family.

Nancy, a former Cal State L.A. student who works for the Alhambra Unified School District, had planned to relax at a week-long yoga retreat, something she had done last year.

Ng left on Oct. 14 and just a few days into her trip, her family said the retreat organizer called to say she had vanished.

She was officially reported missing on Oct. 19 and her family said the worst part is not knowing where she is or what exactly happened that day. The details of her disappearance remain few and far between.

“The last two weeks have been a living hell because when we first got the news that she was missing, we just had so many questions,” Nicky Ng, Nancy’s sister, told NewsNation affiliate KTLA. “What happened? Where is she now? Is there a chance she’s alive? We didn’t know anything.”

Nicky said her sister was staying on Lake Atitlán, a large body of water located within a volcanic crater. The area is also a popular spot for tourist getaways.

Nancy had enjoyed her time on the lake during last year’s excursion so much, she had planned to spend even more time there this year.

“She was saying it’s so beautiful,” Nicky recalled. “Last year, she woke up every morning just to spend some time there by herself without the group and this year was going to be more exciting because they had planned activities on the lake.”

Since Nancy’s disappearance, her family has been on a desperate search for answers. They’ve reached out to the State Department, the FBI and local representatives.

They’re also working with a private search and rescue team in Guatemala which has scoured about 95 percent of the lake by air and land along with divers and drones. 

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“We don’t know where she went in, where she went missing because there’s no corroboration of that,” said Chris Sharpe, Co-Owner of Black Wolf Helicopters, who is assisting in the search for Nancy. “We’ve got a rough idea, but it varies from one side of the lake to the other.”

Sharpe said the primary witnesses, people who may have been with Nancy the day she disappeared, haven’t been forthcoming with the investigation, making things more difficult.

He said the possibilities of Nancy’s disappearance are numerous as they are working to build leads.

“We just don’t know because we’re lacking that vital information,” Sharpe said.

Nancy is the eldest of four siblings and loves spending her free time practicing yoga, traveling, and hiking with her family. She works for the Alhambra Unified School District where she assists students with disabilities.

Despite the setbacks in their search, Nancy’s family remains determined to find her as every second that passes remains a waking nightmare.

“My role here is just to make sure no stone is left unturned and make sure that we try everything we can possible,” said Jonathan Ng, Nancy’s brother.

“We just want her to know that we love her so much and we just really want to bring her home,” Nicky said.

The FBI confirmed to KTLA that although the Guatemalan government remains the lead agency on the investigation, FBI officials are working closely with them. 

Nancy’s family has also been privately funding search efforts. They have created a GoFundMe page to help with search and rescue efforts. 

“Time is of the essence, and we are racing against the clock to bring Nancy home,” her family said in a statement to KTLA. “It has been an ongoing nightmare, not knowing what happened to Nancy or if we will ever get her back. All my family wants is to bring our sister/daughter home. Please help us do so.”