A 79-year-old man with Alzheimer’s disease, who was the subject of a Silver Alert after going missing from his home in Babylon at 1 a.m. Thursday, was found safe 7 1⁄2 hours later outside Lindenhurst High School, police said.

Suffolk County police said Arthur Eriksen was found unharmed about 8:30 a.m.

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Eriksen had last been seen driving his green 2003 Honda Odyssey with a Florida license plate on Montauk Highway in Lindenhurst after leaving his home on Ernest Place.

Concerned relatives contacted police and a Silver Alert was issued by the state Division of Criminal Justice Services, which uses the alerts to provide information to the public helpful to locate missing vulnerable missing adults.