Security forces arrested four facilitators of the Islamabad imambargah suicide attack during raids carried out on Saturday in Peshawar and Nowshera. Among those held is the alleged Afghan mastermind linked to the banned Islamic State (IS), according to security sources. The raids followed technical and human intelligence as part of the ongoing probe into the deadly attack on the imambargah on Islamabad’s outskirts. At least 36 people were killed and many injured when a suicide bomber struck the Friday congregation. Security sources confirmed, "Intelligence and law enforcement agencies conducted raids and made arrests in Peshawar and Nowshera." In Nowshera's Hakeemabad area, a late-night operation led to an exchange of fire between police and suspects. An assistant sub-inspector was martyred, and a constable injured. A police official said, "Yes, a raid was conducted in the district, and an exchange of fire took place. An assistant sub-inspector was martyred and a constable sustained injuries in the crossfire." The official added that the raid was part of the ongoing investigation and involved multiple agencies. He declined to provide more details. The attack targeted Imambargah Qasr-i-Khadijatul Kubra and is the deadliest in the capital since September 2008, when 60 people died in a suicide truck bombing at the Marriott hotel. It also came less than three months after another suicide blast on November 11, 2025 near Islamabad’s G-11 court building that killed 12 people and injured more than 30.