The FBI held a press conference on Thursday, in which they released video images of two suspects in the Boston Marathon bombings.
The authorities are asking the public for help in identifying these men, who were seen carrying black bags at the explosion sites.
The FBI said that the men seemed to be associated.
The new details on the investigation came as President Obama visited Boston today, delivering an uplifting speech at the Cathedral of the Holy Cross and then, along with First Lady Michelle Obama, visiting victims and their families, and hospital staff at Massachusetts General Hospital.
If anyone has any information regarding these men, the FBI asks you to go to BostonMarathonTips.FBI.gov.