Terror group links
-- No connection has been made to any terrorist group or individual.
-- "There is no reporting indicating a foreign connection, or any reaction from al Qaeda," a senior U.S. official said.
-- Obama described the bombings as an act of terrorism, but said it is unclear whether they were the work of a group or "a malevolent individual."
-- The Pakistani Taliban has said it was not involved in the attack.
-- Authorities don't have a sense of what the motive is, and no one is in custody, an official said.
-- DesLauriers, the FBI special agent, asked the public to report anyone who talked about targeting the marathon or showed interest in explosives. He urged anyone who might have heard explosions in remote areas -- possibly by someone testing a bomb -- or seen someone carrying "an unusually heavy, dark-colored bag" around the time of the attack to come forward.
No Saudi connection
-- U.S. officials have said that more than one Saudi has been interviewed, including a 20-year-old student who was questioned as a possible witness.
-- But a U.S. official said the student "was just in the wrong place at the wrong time."
-- The Saudi Embassy in the United States said no Saudi appears to have been involved.
"The embassy stresses that there is no evidence, according to U.S. authorities, of involvement of any Saudi national in the bombings," it said Tuesday in a statement.
-- The investigation is inconclusive.
"They thought they had something with the Saudi national, and that evaporated," a senior law enforcement official said. "There's no sense that they have latched onto anybody or any motive."
-- Authorities are asking those who may have video or pictures taken of the scene around the time of the blasts to call city or FBI hot lines.
-- Cities have stepped up security after the attacks, including Washington, New York, Miami, Chicago, Atlanta and Los Angeles.
-- British police said they are reviewing the security plan for the London Marathon scheduled for Sunday. The marathon will observe 30 seconds of silence and is urging runners to wear a black ribbon to mark the Boston tragedy.
-- "Boston is not going to be intimidated by this," said Secretary of State Kerry, a former U.S. senator from Massachusetts, in testimony to the House Foreign Affairs Committee Wednesday. "But we are going to find out who did this. The police work being done is extraordinary. The FBI is remarkable. There is a great deal of forensic evidence. We are hopeful we can bring people to justice."