Updated

A fourth body has reportedly been discovered in a popular Mexican tourist area, where an American and two Australians vanished last week while on an apparent camping and surfing trip, the local prosecutor's office said in a statement late on Friday.

American Jack Carter Rhoad, 30, as well as Australian brothers Callum Robinson, 33, and Jake Robinson, 30, were last seen on April 27, the Baja California state prosecutor's office previously announced. They did not show up at their planned accommodation last weekend.

Investigators discovered three bodies dumped in a pit while searching for the trio on Friday, although officials have not confirmed if the bodies are those of the missing men.

The fourth body was found nearby, the New York Post and other outlets reported. It's unclear if it's connected to the other three. 

2 AMERICANS FOUND DEAD IN HOTEL ROOM IN MEXICO'S BAJA CALIFORNIA

Missing surfers and a burned out truck

Australian brothers Callum Robinson and Jake Robinson, top left, and US citizen Jack Carter Rhoad, right, who are missing in Mexico. (Reuters)

Forensic tests on the remains will be conducted by a state laboratory, which will allow for positive identification of the bodies, the prosecutor's office said in its statement.

Investigators continue to search the rugged area where the bodies were found for additional evidence, the statement added. 

The bodies were found in a rugged hillside area in the Mexican state of Baja California near the popular tourist town of Ensenada, about 90 minutes south of the U.S.-Mexico border. Video from the scene shows rescuers installing ropes to enter the pit where the bodies were discovered. The site is cordoned off by police, while a navy boat was also visible in the sea nearby.

The site where the bodies were discovered near the township of Santo Tomás, was near the remote seaside area where the missing men’s tents and the burned-out Chevrolet Colorado pickup truck were found Thursday on a remote stretch of coast.

Rescue team workers search for missing tourists in Mexico

Members of a rescue team work at a site where three bodies were found in Baja California. The team have been looking for one American and two Australian tourists who have been reported missing. (Reuters)

It is unclear what types of injuries the victims suffered or how they died.

"There is a lot of important information that we can’t make public," María Elena Andrade Ramírez, the chief state prosecutor said.

Baja California prosecutors said Friday that three people had been arrested and charged with a crime equivalent to kidnapping. It was unclear if they might face more charges.

Ensenada Mayor Carlos Ibarra Aguiar said in a news release that a 23-year-old woman had been detained with drugs and a cellphone that had a wallpaper photo of one of the missing men, The San Diego Union-Tribune reports. Officials didn’t specify how the three people were connected to the investigation, saying only that some were directly involved and others indirectly.

LUXURY RESORT SHUTTERS IN MEXICO'S BAJA CALIFORNIA AFTER MYSTERIOUS DEATHS OF 2 AMERICANS

Missing surfers in Mexico poster

A missing persons' poster of the trio was distributed earlier this week. (Reuters)

Investigators said that a missing persons report was filed 48 hours after the men were last seen, although the prosecutor’s office began investigating as soon as posts began circulating on social media.

María Elena Andrade Ramírez, the chief state prosecutor, said that while drug cartels are active in the area, she said, "all lines of investigation are open at this time. We cannot rule anything out until we find them."

The Baja California Attorney General’s Office has said that it has maintained contact with the FBI and relatives of the victims, through consular agencies.

View of hillside area where rescuers search for missing tourists in Mexico

Members of a rescue team work at a site where three bodies were found in the state of Baja California where one American and two Australian tourists were reported missing.

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On Wednesday, the missing Australians' mother, Debra Robinson, posted on a local community Facebook page an appeal for help in finding her sons and noted that Callum is diabetic.

The Australian media reports that Jake is a doctor, while Callum lives in San Diego and is a member of Australia’s national lacrosse team.

The State Department’s travel advisory lists Baja California under its "reconsider travel" category due to crime and kidnapping.

In 2015, two Australian surfers, Adam Coleman and Dean Lucas, were killed in western Sinaloa state, across the Gulf of California — also known as the Sea of Cortez— from the Baja peninsula. Authorities say they were victims of highway bandits. 

Reuters and The Associated Press contributed to this report.