A New Jersey man has been convicted of plotting an attack on Pope Francis during his visit to Philadelphia in 2015 during the World Meeting of Families.

Santos Colon Jr., 17, of Lindenwold in Camden County, pleaded guilty in a New Jersey federal court Monday, April 3 to one count of attempting to provide material support to terrorists.

Court documents show Colon admitted to acting under the name Ahmad Shakoor in support of the Islamic State, though it is not clear if he was in communication with the terrorist group.

In a statement, the U.S. Department of Justice said Colon planned between June 30 and Aug. 14, 2015 to utilize a sniper to shoot the pope during his public Mass on Sunday, Sept. 27, 2015 on the Benjamin Franklin Parkway in Philadelphia. He also planned to set off bombs in the surrounding area.

Up to several hundred thousand people were in attendance on the parkway that day as the concluding Mass to the World Meeting of Families in Philadelphia and the first apostolic visit of Pope Francis to the United States was celebrated without incident.

Colon, a U.S. citizen and only 15 years old at the time, solicited who he thought would be the sniper in the plot but who in actuality was an undercover agent of the Federal Bureau of Investigation.

Colon scouted the area of the planned attack and instructed the agent “to purchase materials to make explosive devices,” the Justice Department said in its statement.

Colon was arrested in 2015 about two weeks before the papal visit.

Pleading guilty as an adult, he faces a maximum of 15 years in prison and a fine of $250,000. No date has been set for sentencing.

In his plea statement, Colon reportedly has in the past received treatment in a mental health institution.