Michael Larry Madden was a 20-year-old Humboldt State University student who disappeared while camping and fishing at Sand Bar Flat in the Stanislaus National Forest near Sonora, California. He left home on August 10, 1996, with his dog Matilda and camping gear to meet friends; when those friends arrived at the campsite on August 12 they found Michael absent but his gear and a fresh campfire present.

A man identified as Joseph Tine appeared at the campsite shortly after the friends arrived, described as acting suspiciously and repeatedly cocking a pistol. Tine was reported to be wearing boots similar to ones Michael was known to have, although that was never confirmed. Extensive searches including sniffer dogs and divers turned up no trace of Michael; Matilda returned to the campsite four days later, dehydrated and unable to lead searchers to him.

Authorities suspect foul play but no charges have been filed. Some investigators have suggested a possible link to a suspected serial killer in the area, but no conclusive evidence has been produced and the disappearance remains unsolved. If anyone saw Michael at Sand Bar Flat on August 12, 1996, or remembers seeing a man acting strangely near the campsite, please share what was seen.