Iran and the Blast in Iraq

Kamangir (Archer):

Less than twelve years ago a blast in this shrine, located in Iran, happenned. A terrorist organization first claimed the responsibility, but then footprints of Iranian intelligence was found. the whole story was never fully surfaced.

Imam Reza (see) is the eighth Imam in Shia Islam and his shrine is located in Mashhad (see), the capital city of Khorasan, a province in northern east Iran. On June, 1994, a massive blast destroyed portions of the shrine, killing twenty six people (unfortunately, I can't find any picture of the event). The explosion happened in the Ashura decade, the time in each year Shias mourn for Imam Hossein's martyrdom (see). People's Mujahedin of Iran (PMOI), a terrorist Iranian organization based in Iraq at the time, accepted the responsibility. The guy assumed to be responsible for the blast was killed in a shooting.

However, after Saeed Emmami, a high ranking official in Iranian Intelligence, was arrested and charged with assassinating opposition figures, he also confessed that his group had links to the the bombers. This event, like many others in recent Iran's history, was never fully investigated and clarified.

Iran is having a very troubled relationship with the west. And just out of nowhere, a group of gunmen blast a shrine, causing different religious groups in Iraq to fight together. A "good" way to make Americans busy in Iraq. Or maybe as some say "to tell them, Hey! do not mess with us!" Is there any doubt that Iran would be amongst the first parties accused for being behind this (see)?