Allen Talmadge Mathews, 80, went missing from a care facility in San Leandro, California, on May 21, 1998. Mathews, who suffered from dementia, reportedly walked away from the facility that day and has not been seen since. Authorities say extensive searches and investigations produced no significant leads.

Mathews is described as a Black male, 5 feet 7 inches tall, about 147 pounds, with gray hair, brown eyes, an appendectomy scar, and he wore glasses. Given his advanced age and medical condition, investigators have long been concerned about his well-being.

Anyone who remembers seeing Allen Mathews around San Leandro on or after May 21, 1998, or who has other information about his whereabouts is asked to contact the San Leandro Police Department.