CHICAGO (CBS) -- Police are asking for help finding a missing U.S. Army veteran who suffers from Alzheimer's disease and dementia.

Park Forest police said 79-year-old Calvin Holliday was last seen around 2:15 p.m. Sunday on the 200 block of Washington Street.

Holliday is 6 feet tall, weighs 200 pounds, and was last seen wearing a black Kangol hat, a gray sweater with red stripes, and black cargo pants.

Early Walker, co-founder of the nonprofit I'm Telling, Don't Shoot, said Holliday is a retired Army lieutenant, who is also the uncle of a Cook County judge.

Anyone who sees Holliday, or who has information on his whereabouts, is asked to call 911.