The N.C. Center for Missing Persons issued a Silver Alert for John Wrenn Cook, 27, of Clayton who is mentally ill and needs medical attention. His family said he left his home in Clayton on June 16.

Cook is described as 5 feet 10, 165 pounds with short brown hair and hazel eyes. A tattoo on his upper arm says "Radar," which is his nickname.

He was last seen wearing a bright green T-shirt, blue jeans and tennis shoes.

He is thought to be driving a 2004 light green Ford with the North Carolina license plate MRN7926.

Kim Hayes, Cook's aunt, said the family is worried because her nephew sometimes doesn't recognize family members. He has a license, but he isn't usually gone from home for long.

"He only had a half a tank of gas, and he didn't have much money," Hayes said. They wonder whether the vehicle might have been left somewhere out of gas.

Hayes said Cook likes to visit Wal-Mart, bookstores and hobby shops.

"He loves to walk through Wal-Mart," she said. "Wal-Mart draws him like a magnet."

Anyone with information about Cook is asked to call Detective Chris Otto at the Johnston County Sheriff's Office, (919) 989-5000.