WEEHAWKEN - A New Jersey teen was arrested after climbing to the top of One World Trade Center, raising questions about the building's security.

Justin Casquejo didn't have far to go if he wanted to look at the skyscraper. He lives a block from the river with a clear view of the tower. 

On Sunday morning, he decided he wanted a closer look. He sneaked into the construction site and rode an elevator to the 88th floor, and past a reportedly napping security guard. He then climbed 24 more stories to the top, where he spent nearly two hours.

Casquejo took photos of his adventure before he was arrested coming down from the tower. He was charged with trespassing.

"Obviously, it's shocking and troubling, and I don't know how it possibly could have happened," says New York Mayor Bill de Blasio.

Paul De Matteis, director of the Counter Terrorism Assessment Program at John Jay College of Criminal Justice, says Casquejo's stunt exposed serious shortcomings, even for a building still under construction. "If a real attack team had taken this on, rather than a 16-year-old kid, there could have been serious damage to the building and people's lives," he says.

Neighbors say they've known Casquejo and his family for years. He's known as a climber and a daredevil. "He was always playing on the roof, always doing crazy things," says Gina Martinez.

"We take security and these types of infractions extremely seriously and will prosecute violators," Port Authority Chief Security Officer Joseph Dune says. "We continue to reassess our security posture at the site and are constantly working to make this site as secure as possible."

The Port Authority says the security guard has been fired. It took away Casquejo's camera and cellphone. Investigators are looking at the pictures he took.

Some have suggested the teen did authorities a service for exposing shortcomings in security. But De Matteis says Casquejo is no hero, and that he made the United States appear weak.