Richard Burke was last seen in Stony Brook on Nicolls Road at about 9:20 p.m. on Monday, April 4, police reported.
He is described as being 5-foot-5 and 200 pounds, with gray hair and brown eyes.
He was last seen wearing a navy blue sweater, black sports pants, and black velcro shoes, authorities said.
Authorities said Burke has memory loss and bipolar disorder, and he may be in need of medical attention.
Anyone with information about Burke's whereabouts is asked to call SUNY Police Stony Brook at 631-632-7836 or 911, authorities said.
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