By Tuesday morning, ISIS had claimed responsibility for Monday night’s terror attack outside the Manchester Arena that left 22 people dead. Media reports identified the attacker as 23-year-old Salman Abedi, who was known to authorities. Police had also arrested another man in connection with the bombing.

It’s also been reported that the bomber had clear ties to al Qaeda and might have been trained in Libya.

The work of counterterrorism experts is just beginning, though. As the Washington Post reported Tuesday night, the search is on to isolate what could have motivated the bomber.

There might be a breakthrough later Tuesday night when Nightline airs. ABC News has put chief investigative correspondent Brian Ross on the case, and rumor is he’s cross-checked the name Salman Abedi against the database of known Tea Party members provided to him by sources within the IRS.

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