NEW YORK (AP) New York City police are investigating whether a photo of a boy riding a subway train is that of an autistic boy missing for nearly a month.

A 13-year-old snapped the picture Tuesday and later posted it on his Facebook page.

The boy in the photo resembles 14-year-old Avonte Oquendo (ah-VAHN'-tay oh-KEHN'-doh), last seen on Oct. 4 walking out of his Queens school.

The photo shows him sitting and looking straight ahead. He's wearing a beige jacket and green khaki pants.

The teen who took the photo approached the boy and asked if he was Avonte. But the boy didn't respond.

Avonte's parents say they can't be sure that it's their son. Family spokeswoman Penni Horwich says it's amazing a 13-year-old had the wits to take the picture.