A 5-year old girl was abducted from her Philadelphia elementary school on Monday by a woman impersonating her mother, authorities say. The girl was found early the next morning at a nearby park, wearing only an oversized t-shirt and no shoes. She’s currently undergoing treatment to determine if she was sexually assaulted, but authorities say she appears to be physically unharmed.

If it sounds like every parent’s worst nightmare, it is. We bring our children to school or send them off on a bus assuming they’ll be safe there during the day, but when something like this happens, all pretense of safety is ripped away. Police say they have surveillance footage of the alleged kidnapper, who was dressed in traditional Muslim garb and had her face obscured, and school officials say she signed in with a hall monitor with the explanation that she wanted to take her daughter to breakfast. She then went straight to the classroom, a big no-no in any public school. Officials are still working to figure out why she was allowed to bypass the office.

Fortunately in this case, the child has been returned to her parents, but the question of why anyone would impersonate a parent to abduct a child only to abandon her the next day is one that needs an answer. A passerby, Nelson Myers, says he’s glad he happened to be passing by the park on Tuesday morning. The child’s cries drew him, he said, and when he came upon her beneath some playground equipment, she told him she’d been stolen. He wrapped her in his coat and called police.

“She was just mainly shivering and saying that she was cold,” he said. “I’m just glad I was there at the right time.”