NYPD releases new footage of Chelsea explosion

Police have released new surveillance video of the bomb that exploded in Chelsea on Saturday. The video shows people walking down 23rd Street when suddenly there's a flash. People then cover their ears and run for safety. The new video comes as authorities continue to build their case against suspect Ahmad Rahami.

It's been a day of slow, but steady progress in the investigation into the bombings. The wife of Rahami arrived in the U.S. Wednesday night and is cooperating with investigators, but there are still key pieces of this puzzle that are missing.

Federal agents were seen coming out of Sonia's Beauty Salon on Elmora Avenue in Elizabeth, New Jersey. It's right next door to the First American Fried Chicken restaurant and the apartment owned by Rahami's family.  According to neighborhood sources, the alleged terrorist had his beard trimmed at the salon.

NYPD Deputy Commissioner for Counter-terrorism John Miller told CBS that authorities are still not sure if he acted alone.

"The question is could one person make that many devices, cover that amount of ground, do that all by themselves? It's certainly possible, but it's equally possible that there may be others involved," said Miller.

Another troubling mystery: The identity of two men seen in FBI and NYPD wanted posters. Police said the two men picked up a bag on West 27th Street, took the pressure cooker with an attached phone detonator out of the bag, and walked away with the bag. Authorities would like to talk with them as witnesses.

"We need these two guys just to figure out who they are and how they encountered the bag," Miller said. "We want the bag. It may have evidence. It may have explosive residue and other forensics, and it's very valuable."

Miller said there's not yet any evidence of a terror cell, but it's early in the investigation to have a final determination. Rahami remains in custody recovering in a Newark hospital. He is facing a long list of state and federal charges.