Aug. 5, 2017: A blast caused by what the FBI called "an improvised explosive device" rocked the Dar Al-Farooq Islamic Center in Bloomington before dawn, just as a small group of worshipers had gathered for the day's first round of prayers. No one was hurt in the explosion, which heavily damaged an imam's office.

Aug. 6, 2017: Gov. Mark Dayton calls the bombing "an act of terrorism."

Aug. 15, 2017: Calling the investigation its top priority, the FBI in Minneapolis offers a $30,000 reward for information leading to the conviction of anyone responsible for the bombing of the mosque.

Tuesday: Federal authorities announce the arrest of three men suspected of involvement in the attack.