Megadeth's Dave Mustaine and his family are still seeking his missing mother-in-law and the rocker now believes that she was picked up by someone shortly after she went missing.

Mustaine tells San Diego's 'Bob and Coe Show' on 101 KGB that the search for Sally Estabrook has been extensive so far and turned up no results, which leads him to the conclusion that his mother-in-law, who is suffering from Alzheimer's Disease, was picked up by someone who spotted her.

He explains, "She's just plain gone. They had bloodhounds, they had cadaver dogs, they had helicopters, motorcycles, ATVs … everybody. And that's why now we're appealing to the community, expanding the perimeter and trying to make people aware of this, because somebody picked her up. There's no way a 76-year-old woman can trek all the way down a mountain like that. So somebody was being nice and trying to help her. And we're thinking that the person who tried to help her is afraid that maybe they did something wrong. We don't care. We just wanna know where she is."

The rocker says he suspects that the person who picked her may not have come forward due to extenuating circumstances and he adds that he's not looking to get anyone into trouble. "Even the most terrible of convicts still has a mother, and when they're driving down the road and they see this old woman, the person could have pulled over and helped her and have a criminal past and they can't say anything," Mustaine postulates. "It could be somebody of Latino descent that is here without documentation and is afraid that they're gonna get deported. It could be a number of different things. We don't care what the situation is. Just help us find my wife's mom."

Mustaine says he's been happy with the amount of effort that the rescue teams have put in so far, adding that they've gone above and beyond in their search for Estabrook.

Sally Estabrook is 5 feet 4 inches tall, about 145 pounds with shoulder-length blond hair. She was last seen wearing a teal top and white Capri pants. Anyone who sees Estabrook is asked to call 911 or the sheriff's department at (858) 565-5200.

Dave Mustaine Discusses His Mother-in-Law's Disappearance on 101 KGB's 'Bob and Coe Show'