Two small children were photographed playing on the edge of a rooftop in a bizarre child endangerment investigation that has led to the arrest of a New Jersey mother, MyFOXNY.com reported.

The disturbing photos, taken last Thursday by a neighbor, showed the toddlers — a boy and a girl — walking around on the roof of a Jersey City apartment building and even sitting on the edge, sometimes looking down some 30 feet to the ground below.

The mother of the boy, Grecia Taveras, was working and at school that day, and left her child in the care of her 21-year-old sister, Sasha Taveras, who is the mother of the girl, MyFOXNY.com reported.

The grandmother of the children told MyFOXNY.com that Sasha Taveras had a friend over who wanted to smoke a cigarette on the roof, but they accidentally left the door open.

On Friday, child protective services took both children into custody.

“It was a mistake,” Grecia Taveras told MyFOXNY.com. “It was a mistake that just should not have happened, just one second that changed the rest of our lives.”

The distraught family said they want to know why the unidentified neighbor was more interested in taking the pictures than trying to get them off the roof.

Click here for a video report from MyFOXNY.com.