Report: Mother-in-law of Megadeth frontman missing

JULIAN, Calif. -- A search will resume Tuesday in southern California for a missing 75-year-old woman who is reportedly the mother-in-law of Megadeth frontman Dave Mustaine.

Sally Estabrook was last seen around 4 p.m. Saturday at the Pinezanita RV Park and Campround in Julian, about 60 miles northeast of San Diego, reports CBS San Diego. The San Diego Union Tribune reports that she is the mother-in-law of Mustaine, who was also the original lead guitarist for rock band Metallica.

Estabrook reportedly suffers from Alzheimer's. Her husband told deputies that he couldn't find her after he took a shower, reports the Union Tribune.

Mustaine tweeted a request for good thoughts and prayers for his former wife, Pamela Anne Casselberry, as the search for her mother continues.

Search and rescue teams are combing a six mile area around the campground, reports the paper, but the terrain is proving challenging for crews.

"It's hilly, rocky, and there are a lot of ravines," San Diego sheriff's spokeswoman Jan Caldwell told the paper. "Our fear is that she fell down a hill and maybe injured herself."

Estabrook is reportedly 5 feet, 4 inches tall, weighs 145 pounds and has shoulder-length blond hair. She was last seen wearing a teal shirt and white Capri pants. Authorities tell the paper that Alzheimer's has affected her communication skills, but she may respond to her name.

Anyone with information about Estabrook's whereabouts is asked to call the sheriff's department at (858) 565-5200.