Italian police said that a 36-year-old Pakistani named Siyar Khan was arrested on Friday for allegedly participating in a 2009 Peshawar market bombing and taking part in a potential plot against Pope Francis.
The bomb blast in the Peshawar Meena market area in Pakistan killed 130 people and injured many others in 2009.
A legal resident in Italy, Siyar Khan was detected and arrested in Rome while he was getting off from a flight from Islamabad.
One of the investigators, Mario Carta, said that the Khan entered Italy in March 2010 to organise attacks on Rome or the Vatican.
"We have not been able to establish the identity of the kamikaze [bomber]... but we believe he is still at large in Italy, most probably in the region of Olbia, which had become a nerve centre of jihadist activity," Carta added.
The arrest of Khan is an extension of an operation in the Sardinian Island town of Olbia which resulted in the detention of nine suspects of Afghan and Pakistani origin thought to be linked to Al Qaeda.
Italian investigation against terrorism
The operation which ended with the arrest of Khan began six years ago with an illegal immigration case.
From evidence police gained through wiretaps between 2005 and 2012 they believe this alleged network planned an attack on the Vatican in March 2010. Investigators also linked the arrival of a potential suicide bomber from Afghanistan to Rome to the suspected terror plot against the Vatican.
According to the wiretaps, some of the suspects made contact with Osama Bin Laden before his death in 2011. The investigators believe that the same suspects were involved in a Pakistani market bombing in 2009 which caused the deaths of at least 100 civilians. The attacks coincided with the day of Hillary Clinton's visit to Islamabad, the Pakistani capital.
More recently, Italian officials have been taking a threat made by ISIS (ISIS) to conquer “Rome and the seat of Christianity,” seriously and have increased their anti-terrorism efforts.
Al Qaeda began to operate in Pakistan after Western forces replaced the Taliban government in Afghanistan in 2001. After that, many fighters fled to the Pakistani border and started to work in small mobilised groups to carry out surprise attacks on military and civilian targets, causing deaths and disruption.