Before 3 p.m. ET on Monday, April 15, two explosions at the Boston Marathon killed three people and injured more than 180 others, and turned the race into what ABC News said resembled "a war zone."
The explosions occurred almost simultaneously near the race's finish line on Boylston Street, which was crowded with runners and spectators, according to ABC. Thousands of runners were still completing the race at the time of the first explosion.
Massachusetts Gov. Deval Patrick and some city agencies took to social media to inform citizens of the incident. The Boston Police Department, for instance, said via Twitter that it's looking for video footage from the race's finish line, and is sharing other relevant information.
In addition to asking the public to send the Boston Police Department video footage from the finish line, investigators will also be reviewing footage from closed-circuit TV cameras lining Boylston Street and its surroundings. The next step is to run a forensic analysis on the evidence. While the increase in video — both from the public and CCTV cameras — can provide much information, it is a substantial task to examine. For example, according to The Atlantic, the 2011 Vancouver riot brought 1,600 hours of video streaming into that city's police department. The Atlantic added that currently there is no software that can automate the process of examining video.
The FBI analyzes video within its Operational Technology Division, and local police can request help from the Digital Media Evidence Processing Lab at the University of Indianapolis, which is run by the Law Enforcement and Emergency Services Video Association.
In addition to sharing information, such as the tweets embedded below, Patrick asked those who saw anything suspicious to call 1-800-494-TIPS or the Mayor’s Hotline: 617-635-4500.
I have been in touch with the President, Mayor Menino and our public safety leaders. Our focus is on making sure that the area around— Deval Patrick (@MassGovernor) April 15, 2013
Copley Square is safe and secured. I am asking everyone to stay away from Copley Square and let the first responders do their jobs.”— Deval Patrick (@MassGovernor) April 15, 2013
Though #bostonmarathon began as a way to communicate about the race, it is now a hashtag that links to updates about the attack.
Google set up a person finder specifically for the Boston Marathon explosions, where anyone who has information related to a found person can enter that information, or anyone looking for a missing person can conduct a search. The American Red Cross’ Safe and Well website also is designed to connect friends and family following an emergency. Additionally, the Massachusetts Emergency Management Agency also recommends that people can call the mayor’s hotline (617-635-4500) for help with locating others.
At 6:10 p.m. EST on April 15, President Barack Obama addressed the nation. "We do not know who did this, or why," he said. "But make no mistake. We will get to the bottom of this."
The following is a video, courtesy of PBS, from the president’s press conference on Tuesday, April 16, during which he called the bombing “an act of terrorism.”