Two hikers discovered the bones Thursday in a remote area of the famous Mojave Desert park. The hikers were search-and-rescue workers from Riverside County but they were off duty at the time, Inyo County sheriff's spokeswoman Carma Roper said.
Identification for one of the missing tourists was found near the bones, she said.
"We're fairly certain" that the remains are those of one or more of the long-missing visitors, Roper said. However, formally identifying the remains will be a long process, she said. The cause of death also must be determined.
"At this point, it's being handled like a criminal investigation ... but there is no evidence of foul play at this point," Roper said.
The remains were found southeast of Goler Wash, a rugged area accessible only by 4-wheel-drive vehicles. The area is several miles south of the spot where an abandoned minivan the tourists had rented was found months after they were reported missing.
Roper said it would be a relief to solve a mystery that stretches back to 1996.
"I know a lot of people have invested a lot of their time and energy and emotions into concluding the case," she said.
The park near the Nevada border is considered the hottest and driest location in North America. The four who vanished in the 3-million-acre wilderness on July 22, 1996, were Dresden residents Cornelia Meyer, 27; her 4-year-old son, Max; her boyfriend, architect Egbert Rimkus, 34, and his 10-year-old son, Georg Weber.
They had arrived in the United States earlier in the month and were touring in a Plymouth Voyager minivan rented in Los Angeles.
They checked out of a Las Vegas hotel room on July 22 and arrived in Death Valley the same day, records indicated.
Temperatures in the park that week had topped 120 degrees.
The visitors bought an information booklet at the visitor center and then apparently stayed overnight in the park and the next day took a dirt road into a remote area.