A middle school student has vanished after packing a bag and leaving his New Cassel home before dawn Monday, Nassau police said Friday in asking for the public’s help to find him.

Unlike many missing children cases, police have no credible leads on what happened to Amari Young, 13, despite questioning family and friends, and visiting teen hangouts, parks and places with surveillance cameras, Kevin Smith, chief of detectives, told reporters at a news conference.

Investigators have also scoured social media sites and used the department’s real-time intelligence center to find his friends and ask about him, he said.

“We don’t believe he hangs out with a bad crowd. We don’t believe he abuses any drugs of any sort, so this in itself makes it unusual that he’s missing,” the chief said.

His mother, Tiffany Allen, reported her son missing on Monday after noticing his black backpack and some clothes were gone. He left behind his cell phone, she said.

“I just want him to come home,” Allen said. “I just want to know that he’s safe.”

She and her friends will be passing out fliers this weekend in the area, she said.

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A security guard at the boy’s Westbury Middle School reported seeing him Monday and another person reported seeing him at Martin “Bunky” Reid Park in Westbury, but the two sightings have not been confirmed, police said.

Smith said police regularly call and visit the teenager’s mother and his father, who lives in Queens.

“It’s out of character for him to be away this long,” the chief said. “Your average 13-year-old boy doesn’t go missing for five days. It’s possible that maybe he’s staying with friends in the area, and that the adults at that location are unaware that he’s missing from his home.”

Police ask anyone with information to call the missing person squad at 516-573-7347.