5:25pm ET: President Obama is headed to Boston on Thursday.
5:20pm ET: The FBI has stated the explosives were likely placed in a "black nylon bags," and found fragments of nails, BBs, and what may "possibly" be pressure-cooker(s) at the scene.
5:15pm ET: An official with the FBI announced this afternoon that there are no leads or motives at this time, and noone has stepped forward to claim responsibility, though the investigation is still in its "infancy." He asked for members of the public to come forward with any information, noting, "The person who did this is someone's friend, relative, or coworker...someone knows who did this."
4:50pm ET: A friendship between two rivals in the face of tragedy. "We stand united with the Red Sox," tweeted the Yankees on Tuesday. "Bigger than the game. Thank you!," replied the Boston baseball team's account.
4:45pm ET: An update on the victims taken to Boston Medical Center from WHDH-TV 7News.
4:22pm ET: The day after, national guards and police are armed with machine guns in downtown Boston.
3:45pm ET: Marathon runners and citizens of Boston have erected an impromptu memorial at the site of yesterday's blasts.