Update, April 18: The FBI has officially named these two men as the suspects. The agency released photos and videos (below) of the two men the are seeking. If you know these terrorists, call 1-800-CALL-FBI.
Update, April 19: The suspects have been identified as Tamerlan Tsarnaev, 26, and his brother Dzhokhar Tsarnaev, 19. Tamerlan was killed in a shootout with police last night. Dzhokhar is still on the loose. This is believed to be his Twitter account.
Dzhokhar was found hiding in a boat in a Watertown, Mass. homeowner's yard, below. According to reports, shots were fired. The Boston Police has confirmed Dzhokhar is in custody.