MEXICO CITY (AP) — Mexican prosecutors said Friday that a German cyclist and a Polish biker were apparently murdered after forensics tests revealed a bullet wound to the German's head, reversing an earlier statement that suggested the two died in an accident.

Luis Alberto Sanchez, the chief homicide prosecutor for southern Chiapas state, said the bullet that killed German Holger Franz Hagenbusch hasn't been found. It caused entry and exit wounds to his head, but may never be located because it appears the two were killed elsewhere and their bodies dumped in the rural area where they were found in late April.

The two were reported missing while cycling on a rural road that leads east from the colonial city of San Cristobal de las Casas to a jungle area popular with tourists.

Luis Alberto Sanchez says "it is very probable that they were already dead when they were dumped off the side of the highway."

Polish cyclist Krzysztof Chmielewski died of what Sanchez called head trauma caused by a blunt object.

While experts are still trying to determine what object was used, Sanchez said "it was a heavy object that hit his head with great force."

In early May, a Chiapas official had suggested Chmielewski had died in an accidental fall. But the bodies had been out in the woods for a week before they were found and were in bad condition, something that may have delayed the discovery of the real causes of death.

The Polish man's head had been separated from his body, but Sanchez said that appeared to be the result of predation by wildlife or the force of impact when the body was dumped. DNA tests are set to confirm the identities of the bodies.

Sanchez said some of the two men's possessions were missing and that robbery was one of the possible motives being investigated.

Hagenbusch had biked across a number of countries.