Authorities are offering a $1,000 reward for information leading to the arrest of thieves who stole ancient petroglyphs from the Sierra Nevadas in late October.
According to the Los Angeles Times, at least four petroglyphs – some of them located 15 feet above the ground – have been hacked off of lava cliffs in the Eastern Sierra.
The region, known as Volcanic Tableland, is held sacred by local Indian tribes whose ancestors carved hunting images and spiritual designs into lava boulders.
Visitors reported the thefts on Oct. 31. Archaeologists said the carvings – over 3,500 years old – were violently cut from the rock face with power saws.
"The individuals who did this were not surgeons, they were smashing and grabbing," U.S. Bureau of Land Management archaeologist Greg Haverstock told the newspaper last week. "This was the worst act of vandalism ever seen."
Volunteers have stepped up surveillance in the area.
View Ancient rock carvings stolen from Sierra Nevadas in a larger map