Portrait emerges of Salman Abedi, suspected Manchester bomber

The frantic search for clues about his possible connections to ISIS is underway.

Police say they conducted a pair of raids on Tuesday, one in the Whalley Range neighborhood, in which they scoured the suspect’s home, the other in nearby Fallowfield, which police said included a “controlled explosion to enable safe entry.” Authorities also took one man, identified by neighbors as the bomber’s older brother, into custody outside a local grocery store.

A photo of Abedi was first published on the front page of the British newspaper The Sun.

In recent years, Abedi took business classes at the University of Salford in Manchester, where he registered for classes this year, a university spokesperson told ABC News, but hasn’t attended any classes and was not well-known socially.

A senior counterterrorism official told ABC that one reason Abedi may have dropped out of college is because he recently traveled outside the United Kingdom to Libya and possibly other countries, "it seems, to get some skills,” though Syria did not appear to be one of his destinations.

Abedi, the official said, was on the radar of British security officials but time ran out on the surveillance clock without Abedi doing anything nefarious, so authorities apparently moved on. It is unknown, the official added, whether Abedi made the device on his own or if he had help.

Mohammed Saeed, the imam of the local Didsbury Mosque and Islamic Centre, where Abedi sometimes worshipped, told ABC News that Abedi became angry with him after he gave a sermon in 2015 in which he criticized ISIS.

"He was showing me hate, he hated me basically," Saeed said. "I was shocked, shocked and angry. All innocent lives matter.”

The neighborhood, around an area called Moss Side, just a few miles from the concert hall, is considered by police to be a hot bed of ISIS recruitment, according to Dr. Alexander Meleagrou-Hitchens, the research director of the program on extremism at The George Washington University.

“Moss Side is very well known,” Hitchens told ABC News. “A lot of people with petty criminal pasts, involvement in gangs, getting involved instead with ISIS later on.”

According to Matt Olsen, the former director of the National Counterterrorism Center and an ABC News contributor, the most pressing questions have yet to be answered.

“The investigators need to focus and are focused on who else may be involved, where did this individual learn to build a device like this, to carry out an attack like this,” Olsen said. “The real question is, is there a cell that goes beyond this individual.”

ABC News’ Rhonda Schwartz, Pete Madden, Cho Park and Alex Hosenball contributed to this report.