The discovery of a skull by a hiker Sunday near Twentynine Palms may be connected to human remains found earlier this month in the same area, authorities said.
Three people, including two former Marines, were arrested after the first discovery and booked on suspicion of murder, the San Bernardino Sheriff's Department said.
The hiker, retired Marine Lt. Col. Charles Sherry, said he told authorities that he had found a machete in the area a few weeks ago. Sherry said he thought nothing of it until Sunday morning, when his dog found a skull in the same place. Sherry marked the location and called the Sheriff's Department.
Officials said tests are necessary to determine whether the skull matches the other remains and whether the machete was the murder weapon.
The investigation began Dec. 31, when sheriff's investigators got a tip that someone may have been killed near Twentynine Palms, a high-desert town that abuts the nation's largest Marine Corps base.
On Jan. 3, human remains were found in the Sugarbowl area.
The same day, deputies arrested Allen K. Patterson, 23, a former Marine from New York, on suspicion of murder.
On Jan. 17, they arrested a 17-year-old, whose name has not been released, and Justin Van Meter, 22, also a former Marine of Twentynine Palms, said Robin Haynal, a sheriff's spokeswoman.
Investigators have said the victim, whom they have not named, may have been targeted because the suspects believed he was supplying information to the police. However, authorities have not disclosed what that information was. They have also said the victim was not an informant.