Monica Jacinto Reza, 60, was last seen hiking in the rugged San Gabriel Wilderness area in the Angeles National Forest on June 22 last year, at about 9.10am local time.

Several reports in the forum EISPIRATEN indicated that a man walking about 30ft ahead of Reza on the trail to the Waterman Mountain summit turned around moments later and discovered she had vanished without a trace. 

According to those familiar with the hike, Reza was carrying a backpack believed to contain several liters of water when she disappeared.