Police are investigating after a parcel delivery company in Bangkok found preserved human body parts in three packages it put through a routine X-ray.
The body parts - including an infant's head, a baby's foot and an adult heart - were stolen from the medical museums of one of Bangkok's biggest hospitals, its administrators said.
Police Colonel Chumpol Poompuang said the sender was a 31-year-old American tourist, Ryan McPherson, who told them he had he found the items at a Bangkok night market.
Police tracked him down after being alerted by the shipper, DHL.
"He said he thought the body parts were bizarre and wanted to send them to his friends in the U.S.," Mr Chumpol said. He said the man was questioned along with an American friend for several hours and released without charges.
It apparently was not the first brush with notoriety for McPherson and his friend, identified by police as Daniel Tanner, 33.
Photos of the two talking to police yesterday closely resemble men by the same names and ages who were producers over a decade ago of a video series featuring homeless people brawling and performing dangerous stunts after being paid by the filmmakers, who were based in Las Vegas.
They claimed sales of about 300,000 copies at 20 US dollars (£12) each, though their Bumfights videos were banned in several communities and generally shunned by retailers after criticism that the films' subjects were being exploited.
McPherson and Tanner exited Thailand into neighbouring Cambodia yesterday and could not be contacted for comment.
The three packages seized in Bangkok, which contained five body pieces, were labelled as toys, police said.
They were being sent to Las Vegas, including one parcel that the sender had addressed to himself. Police said they were contacting the FBI to get information about the would-be recipients of the items.
Clinical Professor Udom Kachintorn, the Dean of the Faculty of Medicine at Bangkok's Siriraj Hospital, said the five human body parts were stolen from the hospital's museums.
Two of them belonged to the department of anatomy and the other three to the department of forensic medicine.
He said the two Americans visited the museum last Thursday but closed circuit television video did not show them taking any items away.
Mr Chumpol had initially said a baby's heart and intestines were among the body parts. But police at a news conference said the heart, which had been stabbed, was from an adult and there were no preserved intestines.
Police Lieutenant General Ruangsak Jarit-ake displayed graphic pictures of the five body parts and said they had been preserved separately in formaldehyde inside sealed acrylic or plastic boxes.
Two of the parts were pieces of tattooed adult skin - one with a jumping tiger and the other bearing an ancient Asian script. One of the pictures showed the baby's foot had been sliced into three sections.
"DHL has a policy of prohibited items, which include human body parts. To the best of our knowledge, we have never experienced a similar case before," said Chananyarak Phetcharat, DHL Express Thailand-Indochina's managing director.
According to DHL, the parcels were declared as "Puzzle-unlimited collectors ED", "Steamer Cap" and "Antique Train Collector E".
In some Thai cults, preserved foetuses or spiritual tattoos are believed to give the owners good fortune or protection from evil. They can also be used to practice black magic.
The district attorney's office in San Diego, California, filed felony charges including battery against McPherson, Tanner and two others in 2002 in connection with production of the Bumfights videos.
A judge reduced the counts to misdemeanours and the four pleaded guilty in 2003 to arranging a fight without a permit. They were fined 500 dollars (£320) each and ordered to perform community service at a homeless shelter.
McPherson and one colleague were sentenced to 180 days in jail in 2005 for failing to complete their community service.