In an update on the probe, Chief Justice of the Fars Province Kazem Mousavi said on Monday ten suspects involved in the tragic incident were arrested, adding all of the suspects were of foreign nationalities.
Mousavi also said the police discovered the safe house of the terrorists.
The main assailant opened fire at the pilgrims with an AK-47 rifle and made an attempt to enter a more crowded area of the shrine before being arrested.
During the initial investigation, the assailant identified himself as Rahmatollah Norouzov from Tajikistan.
The Daesh terrorist group claimed responsibility for the assault.
The shrine came under a similar terrorist attack last year, when an armed assailant opened fire on people inside the shrine, killing 13 pilgrims, including women and children, and injured dozens more before he was shot and injured by security force and later succumbed to his injuries.