UPDATED: 14 July 7:35 a.m. Authorities say the son of a Boston police captain plotted to detonate pressure-cooker bombs at an unidentified university in a terrorist act aimed at supporting the Islamic State group.

The FBI says 23-year-old Alexander Ciccolo talked with a cooperating witness in recorded conversations about his plans.

Ciccolo was arrested July 4 after he received four guns he ordered from the witness, who was working with terrorism investigators.

Two law enforcement officials told The Associated Press that Ciccolo's father, Capt. Robert Ciccolo, alerted the FBI last fall that his son had a long history of mental illness and was talking about joining the Islamic State. The officials spoke on the condition of anonymity because they weren't authorized to release details.

Ciccolo's bail hearing is Tuesday in federal court in Springfield.

Prosecutors have arrested the son of a Boston police captain in a plot to commit terrorist acts on behalf of the Islamic State group.

Alexander Ciccolo is accused in a criminal complaint unsealed Monday of receiving four guns July 4 from a person cooperating with the Western Massachusetts Joint Terrorism Task Force.

An FBI affidavit says the 23-year-old Adams resident had talked with the cooperating witness in recorded conversations about his plans to commit acts inspired by the Islamic State group, including setting off pressure-cooker bombs at an unidentified university. According to the affidavit, he said the attack would include executions of students broadcast live online.

Before his arrest, agents had observed Ciccolo buying a pressure cooker similar to those used in the 2013 Boston Marathon bombings.