The young men, who sources described as being well-dressed, opened the bag and took the bomb out, sources said, before placing the explosive into a garbage bag and walking away with the rolling suitcase.

In doing so, investigators believe they inadvertently disabled the explosive, sources said. That allowed investigators to examine the cellphone attached to the bomb intact and discover that it was connected to the family of Rahami.

From there, they were able to identify pictures on social media of Rahami’s family and of him, and they matched one of his photos to surveillance footage captured in Manhattan.