(NewsNation) — Amy Bradley suddenly vanished from a Caribbean cruise in March 1998 and has been the subject of various theories about what happened to her.

Bradley, 23 at the time she went missing, was on Royal Caribbean’s Rhapsody of the Seas with her parents and brother as they traveled to Curacao.

The night she disappeared, she was out partying with her brother until the early hours of the morning. The last time she was seen, her father woke up and noticed her legs on the chair of the balcony at around 5:30 a.m.

By 6 a.m., Bradley was gone.

In July, Netflix released “Amy Bradley Is Missing,” a three-part docuseries detailing her mysterious disappearance and the many theories that have arisen in the 27 years since. The series has reinvigorated interest in the case and brought Bradley’s story back into the public eye.

The FBI investigation into her disappearance remains open, and there is a $25,000 reward for information that leads to her recovery.

Falling overboard

A central theory concerning Bradley’s disappearance is that she fell or jumped off the boat, although some believe that cannot be the case.

One version of the theory suggests that she was intoxicated and tripped and fell overboard. Others suggest it was merely an accidental fall caused by sudden movement of the ship.

According to The Charley Project, a public database for missing persons cases, some theorists do not believe Bradley fell overboard because the ship was close to shore at the time and “witnesses would have undoubtedly heard or seen any accident.”

She was also a registered lifeguard and a strong swimmer. Her body was never found when the water was searched.

Suicide

A darker theory related to falling overboard is that she jumped intentionally.

Speculation about Bradley’s relationship was raised in the documentary, and some theorists suggest she was going through a rough patch with her girlfriend before the cruise.

However, her family believes it is unlikely she would have harmed herself. She had recently graduated from college and had a new job lined up with a computer consulting firm. She had sent postcards to friends and planned to pick up a dog she adopted when the cruise ended.

“She had just moved into her new apartment and was starting a new job on the following Monday. She had so many plans and was so happy about all of them,” Iva Bradley wrote in a blog post on the International Cruise Victims’ website.

Murdered on the ship

On the night she disappeared, Bradley was seen dancing with the bassist of the ship’s band, Alister “Yellow” Douglas. Witnesses and surveillance footage confirmed the interaction.

Some passengers also alleged they saw Bradley with Douglas on an upper level of the ship at around 5:45 a.m., within the time window she went missing.

The FBI questioned Douglas following her disappearance. He voluntarily took and passed a polygraph test.

No evidence has linked Douglas to the case, and he has never been charged with any wrongdoing.

Kidnapped and/or trafficked

Since her disappearance, there have been numerous alleged sightings of Bradley, many suggesting she was trafficked and held by captors. Many of these accounts are documented on the amybradleyismissing.com online forum.

A month after she vanished, the Bradley family returned to Curacao to search for her. A taxi driver recognized them and claimed he had seen Bradley running and searching for a phone shortly after she went missing, but a search of the area turned up nothing.

That same year, a Canadian tourist reported seeing a woman with Bradley’s distinct tattoos on a beach in Curacao. She was with two men who led her away after giving the tourist suspicious looks. Authorities searched the beach and found nothing.

Months later, a U.S. Navy officer said he met Bradley in a brothel in Curacao, where she asked him for help. He claimed he left without reporting the encounter for fear of losing his job. The FBI later investigated the brothel but found no evidence.

In 2005, the Bradley family received anonymous photos from an adult website showing a woman who resembled Amy. The site was based in the Caribbean, but the FBI was unable to trace the IP address, and the woman’s identity remains unconfirmed.

Fled the ship to start a new life

One theory, supported by little evidence, suggests Bradley left the ship voluntarily to start a new life in the Caribbean.

The only indication of this, according to a Netflix companion article on the docuseries, is “a pattern of IP addresses, traced to Barbados, logging into the amybradleyismissing.com forum on key family anniversaries and holidays.”

What her family believes

Bradley was traveling with her parents, Iva and Ron, and her brother, Brad. Though she was legally declared dead in 2010, her family maintains she was abducted and is still alive.

“Somebody knows something, somebody saw something, somebody heard something, somebody told somebody something,” Iva Bradley says in the docuseries

Brad Bradley told NewsNation’s “Banfield” that they believe she was “targeted,” “taken” and “removed from the ship.”

“There’s a lot of haters online that say a lot of nasty things and basically say she’s gone, she fell over, she jumped over. I can guarantee those two things didn’t happen,” he told WWBT.