Both the NYC and FBI have been very quick and thorough in their investigation to determine a suspect in the NYC bombings. Because the investigation is ongoing, there is a lot of information that is not being shared with the public. However, the investigators would not publicly name a suspect unless they had solid evidence against him.
The use of pipe bombs and physical evidence will help to pin down a suspect for the New York explosions. There was also surveillance videos that will help to determine the crime. And there are known terrorists and groups that the police are aware of and they have been monitoring. The police have just found a suspect that they have named in connection with the bombings and will bring him in for questioning.
It is clear there is enough evidence to determine Ahmad Khan Rahami is the key suspect for the blasts in New York. His image was seen on videotape in two locations, and the police have quickly identified him as a person of interest. A backpack full of explosives was found near his home in Elizabeth, N.J., making it more likely he is the guilty party.
No, police should dig deeper for more evidences. For now, the suspect is Ahmad Rahami. He was caught on surveillance camera. But there are some biases here. It doesn't just so happen that Rahami is another Muslim, in the midst of all the waves of Americans against Islam and ISIL in the world. We should get more evidence, to be sure that it is him.