(Reuters) - A New Jersey teen has pleaded guilty to participating in a plot to try to kill Pope Francis in 2015 during a public Mass in Philadelphia, according to a statement by federal prosecutors.

Pope Francis celebrates his final mass of his visit to the United States at the Festival of Families on Benjamin Franklin Parkway in Philadelphia, Pennsylvania September 27, 2015. REUTERS/Jim Bourg

Santos Colon, 17, admitted on Monday in a federal court in Camden, New Jersey, that he attempted to conspire with a sniper to shoot the Pope during his visit in Philadelphia and set off explosive devices in surrounding areas.

Colon engaged with someone he thought would be the sniper from June 30 to Aug. 14, 2015, but the person was actually an undercover FBI employee, according to prosecutors. The attack did not take place, and FBI agents arrested Colon in 2015.

“Colon engaged in target reconnaissance with an FBI confidential source and instructed the source to purchase materials to make explosive devices,” prosecutors said in a statement on Monday.

Matthew Reilly, New Jersey U.S. Attorney’s Office’s spokesman, said on Tuesday that there was nothing in the court documents that addressed a possible motivation. Some media outlets had reported Colon’s actions were part of a plot inspired by Islamic State, known by some as ISIS.

“There is no mention of ISIS or any specific organization in any of the court papers or in any of the factual basis questions he was asked in court during the plea hearing,” Reilly said in a email to Reuters.

A U.S. citizen from Lindenwold, New Jersey, Colon was charged as an adult on Monday with one count of attempting to provide material support to terrorists.

He faces up to 15 years in prison and a fine of $250,000, or twice the amount of any financial gain or loss from the offense, prosecutors said. No date has been set for sentencing and the investigation is ongoing.

Colon’s attorney did not immediately respond to a request for comment.

The Pope visited Philadelphia on Sept. 26 and 27, 2015, to hold a public Mass, attracting hundreds of thousands of people during his biggest event in the United States.

The Archdiocese of Philadelphia spokesman Kenneth Gavin expressed gratitude in an statement on Tuesday to law enforcement “who worked to provide a safe atmosphere for the Holy Father and those who traveled from around the world” during the event.