NEW YORK - The Harmony of the Seas cruise ship, one of the biggest in the world, with its multiple-deck waterslides, zip line and surf simulators, is a favourite among families.

But the discovery of a hidden camera in a public bathroom during a recent sailing has many passengers questioning their enthusiasm.

This is especially after the Federal Bureau of Investigation (FBI) said minors who appear to be as young as four or five years old had fallen victim to video voyeurism on board.

According to an FBI affidavit, a man identified as Jeremy Froias allegedly hid a Wi-Fi camera in a top deck bathroom in the cruise ship on April 30.

That was a day after the Royal Caribbean ship departed from Miami for a seven-night eastern Caribbean cruise.

The camera lens was pointed towards the toilet.

The bathroom was located close to one of the ship’s surf simulators and many passengers used it to change into their swimsuits.

A day later, the camera was spotted by a passenger who reported it to the ship’s security staff.

They found hours’ worth of footage showing more than 150 people, including what appear to be at least 40 minors – some of whom were at least partly naked, the charging document said.

The ship stopped in Puerto Rico, where the FBI arrested Froias and charged him with video voyeurism and attempted possession of child exploitation material.

“Individuals are seen coming into the bathroom to either use the toilet or to change into or out of swimsuits,” the affidavit says. “Froias’s camera captured these individuals in various stages of undress, including capturing videos of their naked genitals, buttocks and female breasts.”

Froias is a former cyber-security officer for the Central Florida city of Kissimmee.

Footage retrieved from the camera shows Froias installing the device, the affidavit said.

During an interview with the cruise ship security personnel on May 1, he admitted to placing the camera in the bathroom, according to court documents.

Mr Leo Aldridge, a San Juan-based lawyer representing Froias, declined to answer questions about the case.

The FBI did not return a request for comment.

Froias appeared for a detention hearing in Puerto Rico this week, and a federal judge ordered his release on the condition that he pay a US$25,000 (S$33,000) bond, wear an electronic monitoring device and surrender his passport.

He is not allowed to access the Internet or have unsupervised contact with minors younger than 18, including his two children.

Mr Jim Walker, a Miami-based maritime lawyer who has represented victims in other voyeurism cases, questioned the amount of the bond.

“A US$25,000 bond might be appropriate for a single victim, but considering there are at least 150 victims and many dozens of children, according to the FBI affidavit, a bond should not be less than US$1 million,” he said. He said he has been contacted by passengers who were on the Harmony of the Seas during the incident.

Passengers said Royal Caribbean had failed to notify them about the hidden camera during and after the sailing. They said they found out through the media and an FBI notice seeking to identify potential victims.

“It’s terrifying that passengers and their children were filmed secretly while they were naked using the bathroom,” said Ms April Wise, 52, who was on the cruise with her husband and niece. “Thankfully, we didn’t use that bathroom, but thousands of people were on the ship and they still don’t know if they were filmed or not. It’s unacceptable that Royal Caribbean has not contacted the victims.”

Royal Caribbean declined to comment, but e-mailed a statement, saying: “We are aware of an incident that occurred on board Harmony of the Seas’ April 29 cruise. The matter was immediately reported to local and federal law enforcement and the guest involved was removed from the ship by the authorities for further investigation. As this is an active case, we are unable to share any more details at this time.”

It is not the first time that such an incident has occurred on a cruise ship.

In March, an MSC Cruises crew member was caught filming women in a restroom.

In 2017, a family found a hidden camera pointing towards their bed in their stateroom on board the Carnival Fantasy, but after conducting an investigation, the cruise company said the camera had not been operational.

“It’s so easy for predators to buy small cheap cameras these days,” Ms Wise said. “Checking for them needs to be part of cruise ship security protocol.” NYTIMES