A young couple who went missing while hiking in Joshua Tree National Park, California, died in a murder-suicide pact, according to authorities.

The bodies of Orange County residents Rachel Nguyen, 20, and Joseph Orbeso, 22, were identified in a remote canyon, the San Bernardino County Sheriff's Department said.

Based on gunshot wounds and evidence located at the scene, detectives believe Orbeso shot Nguyen before turning the gun on himself. The couple were found in an embrace.

So, far the motive for the shooting is not clear but authorities say investigations are ongoing.

The pair went missing earlier this year after they went hiking in the vast protected area in south-eastern California which covers more than 1,200 square miles of the Mojave and Colorado deserts. The owner of a bed-and-breakfast where the couple were staying informed authorities that they had not returned on July 28.

US National Park Service rangers later found the couple's unoccupied car near the head of one of the trails. A search and rescue team was dispatched, and the next day help arrived from the county sheriff's department.

The search involved 250 people on the ground aided by dog teams, officers on horseback and aircraft crews. They spent nine days scouring the challenging terrain, before the search was scaled back. The bodies were finally found on 15 October.