A young couple who disappeared in Joshua Tree National Park in California nearly three months ago died in a murder-suicide, investigators said in a statement Friday.

The latest investigation into the incident has led officials to believe that one of the missing hikers, Joseph Orbeso, 21, shot and killed his girlfriend, Rachel Nguyen, 20, before turning the gun on himself. However, a motive for the possible murder is yet to be discovered.

"Based on evidence located at the scene, detectives believe Orbeso shot Nguyen, then shot himself," the sheriff’s statement said. "The investigation into Orbeso’s actions remain under investigation."

"There is nothing left behind to give the investigators or the family any indication of why this happened," Cindy Bachman, a Sheriff’s Department spokeswoman told the Orange County (OC) Register.

"There was nothing like a note or a phone call to explain the circumstances that we found," she added. "It’s unfortunate because it leaves questions for their family."

Visible injuries were found on the bodies by the deputies from Morongo Basin Sheriff's Station. After the Homicidal Detail was called in to take over the investigation, an autopsy by the San Bernardino Coroner’s Office determined the injuries to be gunshot wounds, the report by the OC Register said.

Investigators also found a handgun at the scene registered to Orbeso, San Bernardino sheriff’s spokeswoman Cindy Bachman said, according to the BBC.

She told reporters that there was no indication that Orbeso may have been planning to hurt Nguyen.

"I’m not aware of anyone coming forward to offer information that Rachel was in any danger or that there was anything planned to cause harm to her," she said.

When the bodies were found on Oct.15, they appeared to be locked in an embrace. "It did appear that way, but we’ll really never know," Bachman said.

Orbeso might have been in possession of the gun, he was employed as a security guard at a Long Beach golf course, said Orbeso’s best friend, Austin Young and added he did not believe his friend murdered Nguyen.

"That is not the kind of person Joseph is," Young said. "I think he brought a gun out there to protect Rachel. I think they got lost and were suffering in 100-degree heat."

"They had a choice of a slow and painful death or a quick death," he added. "And they made the choice of a quick death. Joseph wouldn’t do it (the shooting) unless Rachel said she couldn’t take it anymore. I don’t want Joseph to go down as a murderer."

Nguyen’s family also said in a statement that the situation was "very difficult for the family" and that they did not hold any grudge against Orbeso.

"It was explained to us by the investigators on scene, with the circumstances and positioning of the bodies, that they believe this was a sympathetic murder-suicide. We hold no grudges against Joseph or the Orbeso Family," the statement said.

“We extend our heartfelt condolences to the Orbeso Family, and that they will remain in our prayers. We thank God that we’ll be able to give Rachel a proper burial and lay her to rest,” it further added.

The pair was reported missing on July 28  after the police were informed by the owner of a bed and breakfast inn in the Morongo Basin area where the two were staying that they had not returned from a hike since the same morning. The bodies were recovered on Oct. 17, after they were found two days prior.