Missing hikers Rachel Nguyen, 20, and Joseph Orbeso, 22, died in an apparent murder-suicide, according to the Morongo Basin Sheriff's Department. Orbeso shot Nguyen before shooting himself, detectives believe, based on gunshot wounds and evidence located at the scene, according to the statement.

The incident remains under investigation, but authorities don't have a motive, the San Bernardino County Sheriff's Department's Cindy Bachman told KPCC.

"The reasons for him shooting Rachel and then shooting himself, we may never really know why he did that. As far as I know, the investigators don't have any evidence that there was any plan for him to cause any harm to Rachel," Bachman said.

They were initially reported missing on July 28 when a bed and breakfast owner reported that Nguyen and Orbeson, his guests, had left to go hiking in the Joshua Tree National Park and hadn't returned to check out. Authorities also located the couple's vehicle in the park later that day, with the hikers nowhere to be found.

"They were out there for a long time. We don't know if that played a part in them, him deciding that it was time. Unfortunately, we will probably never know that," Bachman said. "Another unfortunate part of this is it's unlikely that the coroner will be able to determine the condition, their health prior to the shooting, or when exactly that shooting occurred. If it was weeks, or more, months into the search for them."

Orbeso's father had said earlier this week that he believed the bodies that had been found belong to his son and the son's girlfriend, Nguyen. Their bodies were later positively identified.

Their bodies were found locked in an embrace, San Bernardino County Sheriff's Department spokeswoman Jodi Miller said earlier this week, according to the Associated Press.

More than 10 of of the search personnel trying to find them suffered injuries during the search for the hikers. The full-scale search continued until Aug. 6 before being scaled back due to a risk versus reward analysis, according to the Sheriff's Department.