Missing California woman's haunting last video shows her kayaking in Guatemala

Family members of the California woman who disappeared while on a yoga retreat in Guatemala have shared an eerie final video of her kayaking from the coast, questioning the local authorities' theory that she drowned.

In a video shared with "Good Morning America," the 29-year-old Nancy Ng, of Monterey Park, can be seen smiling and waving from a kayak on October 19, just before she vanishes while remaining close to Lake Atitlan.

The Guatemalan prosecutor’s office said that a woman with Ng told authorities that they advanced “approximately two kilometres deeper into the lake, where the missing woman tells” the witness that “she wants to swim.”

“And that is when she drowns,” prosecutors told ABC News, with rescuers saying they found her empty kayak.

However, Ng's family denies that simple explanation for her disappearance, claiming it took over 24 hours and others remain silent.

“There are people that witnessed what happened, within the group, that haven’t come forward,” Nancy’s sister Nicky Ng told ABC News in an emotional interview. “We’re racking our brain as to why they wouldn’t want to come forward and help if nothing nefarious happened.”

According to fire and rescue officials, Ng was last seen about a half-mile from shore and her kayak was found empty.

The FBI has offered resources for the search, while the US State Department is monitoring the investigation and in contact with Guatemalan officials.

“My dad … he keeps his phone next to him at night,” the missing woman’s sister said.

“He’s hoping for a ransom call, you know, something that will prove that Nancy might still be alive and that she’s out there, that she’s waiting for us to find her,” she said.

Additionally, the family has also hired a private search team led by Black Wolf Helicopters owner Chris Sharpe.

“We’ve searched 99% of the lake — that’s was with helicopters, drones, boat crews,” Sharpe said, adding that the terrain and a lack of information have complicated search efforts.

“For me, this is now becoming a criminal investigation because the witnesses who were there at a material time are not being forthcoming,” he told ABC 7.

Ng, a former Cal State law student and fitness enthusiast, works with special-need kids in the Alhambra Unified School District and was attending a retreat for the second time with her little sister, who had enjoyed the experience and the beautiful area she was staying in.

“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,” she said.