A shipping company in Bangkok put a trio of packages bound for the United States through a routine X-ray and made a startling discovery -- inside were a variety of preserved human parts, including an infant's head, three babies' feet and a tiny heart.

The shipping company, DHL, alerted police who tracked down the sender, a 31-year-old American tourist who said he found the items at a Bangkok night market, said Police Col. Chumpol Poompuang.

"He said he thought the body parts were bizarre and wanted to send them to his friends in the U.S.," Chumpol said, adding that the man was questioned for several hours and released without charges. The three packages were being sent to Las Vegas, including one that the man had addressed to himself.

Among the baby body parts there was also an infant's intestines and two pieces of tattooed skin from an adult, Chumpol said. All the pieces were preserved separately in formaldehyde inside sealed acrylic boxes.

Police said the method of preservation appeared to be professional and were investigating if the parts were stolen from medical institutes.

In some Thai cults, preserved fetuses or spiritual tattoos are believed to give the owners good fortune or protection from evil. They can also be used to practice black magic.

In 2012, a British citizen was arrested with six roasted fetuses covered in gold leaf after a tip-off that infant bodies were being sold through a website offering black magic service.