Previous story: The FBI on Thursday afternoon released photo and video of two suspects wanted in connection to the bombings during the Boston Marathon. More photos were released at midnight eastern time.
At the time, the suspects were identified only as "Suspect 1" and "Suspect 2." They were seen walking together through the crowd toward the finish line of the race.
"Identifying and locating those responsible is now our highest priority," said FBI Special Agent In Charge of the Boston area, Richard DesLauriers.
Suspect 1 was wearing a black baseball cap with a white symbol on the front, a white T-shirt, black winter jacket, khaki pants and dark shoes. He was carrying a bulky black backpack, with both straps over his shoulders.
Suspect 2 was wearing a white baseball cap on backwards, a black jacket, black pants and black shoes. He was carrying a white or gray backpack with black trim, slung over one shoulder.
Suspect 2 was seen putting a backpack down in front of the Forum Restaurant.
"We know the public will play a critical role in identifying these individuals," DesLauriers said.
The explosions on Monday killed three people and injured more than 180.
"For more than 100 years, the FBI has relied on the public to be its eyes and ears," DesLauriers said. "With the media's help, in an instant these images will be delivered directly into the hands of millions around the world."
Anyone with information about the suspects is asked to contact the FBI at https://bostonmarathontips.fbi.gov/ or call 1-800-225-5324.
DesLauriers spoke directly to people who might be loved ones or friends of the bombers, urging them to take the tough stand and turn them in.
"Somebody out there knows these individuals as friends, neighbors, co-workers or family members," DesLauriers said. "Though it may be difficult, the nation is counting on those with information to come forward and provide it to us."
The suspects are considered armed and dangerous. DesLauriers advised against anyone but law enforcement approaching them.
7NEWS reporter Marc Stewart asked Metropolitan State University criminologist Allison Cotton about the men’s appearance, including the fact they look so young.
"Members of organizations do recruit people who are young. People who are naive. People who are inexperienced. People who are easily manipulated,” said Dr. Cotton.
Adding to the uncertainty, the men look so ordinary.
"Somebody's wearing a T-shirt. The other one's wearing a hoodie. There's no consistency here. You wouldn't even know they knew each other," said Dr. Cotton.
Yet, Dr. Cotton says, photo enhancement could detect tattoos or birthmarks. Now that investigators have the suspects' images, they can run them through databases of suspected or known terrorists.
The FBI's goal is to get the public's attention and persuade people to come forward if they know these men.
"If you saw your brother or your sister or your neighbor on this video, hopefully you would be sufficiently scared into protecting yourself, enough to call the FBI," Dr. Cotton said.
Cotton points out these cases can take time to solve, even with lots of evidence. She noted cases like the Olympic Park Bomber, the Unibomber and the BTK killer.