2:42 p.m. ET: "Contrary to widespread reporting, there have been no arrests made in connection with the Boston Marathon attack," the FBI said in a statement. "Over the past day and a half, there have been a number of press reports based on information from unofficial sources that has been inaccurate. Since these stories often have unintended consequences, we ask the media, particularly at this early stage of the investigation, to exercise caution and attempt to verify information through appropriate official channels before reporting."
2:33 p.m. ET: Senior law enforcement officials tell ABC News no suspect has been arrested yet, despite some early reports.
1:44 p.m. ET: Boston University confirms Lingzi Lu, 23, a graduate student there was the third victim killed in Monday's terror attack at the Boston Marathon.
1:37 p.m. ET: An arrest is imminent or may have already taken place in the Boston bombings, reports ABC affiliate WCVB-TV. Surveillance video taken by cameras at Lord & Taylor on Boylston Street helped identify a suspect placing a bomb.
1:34 p.m. ET: Authorities are close to identifying a suspect responsible for Monday's Boston Marathon bombing, officials tell ABC News.
1:06 p.m. ET: Boston police and FBI to hold press conference at 5 p.m.
- Boston Police Dept. (@Boston_Police) April 17, 2013
12:25 p.m. ET: White House press secretary previews the president's upcoming remarks in Boston, the speech he says: "will be one of resolve; it will be one of commonality we all feel as Americans with the people of Boston."
12:20 p.m. ET: First lady Michelle Obama will join the president in Boston on Thursday for an interfaith service honoring those killed in Monday's attack.
12:18 p.m. ET: "The president has been briefed regularly on the incident in Boston," said White House Press Secretary Jay Carney, adding that President Obama met with his national security team this morning. "The full weight of the federal government is behind this investigation," he said.
10:55 a.m. ET: Oklahoma City police ordered the evacuation of City Hall after a stolen U-haul was found abandoned outside the building. Several blocks around the truck have been cleared and the bomb squad has been called in to investigate. Oklahoma City was the site of a domestic terror bombing in 1995. Across the country, cities and citizens have been on alert since Monday.
10:15 a.m. ET: The FBI has received more than 2,000 images from the public since making a pitch for videos and photos of the blast site. All of the images are being analyzed on site by FBI analysts dispatched from Quantico, Va.
9:30 a.m. ET: Of the 23 people brought to Boston Medical Center, 19 patients remain there is morning, according to Dr. Dr. Peter Burke, chief of trauma surgery. Two patients there, including a 5-year-old, remain in critical condition.
Twelve of the original 31 patients taken to Massachusetts General Hospital remain there. Eight are in critical condition, according to the Associated Press.
At Beth Israel, 13 of the 24 people sent there remain in the hospital. Boston Children's is still treating three of its original 10 patients. Tufts Medical Center has released half of its 14 bombing patients, according to the AP.
On Monday, two small but powerful bombs exploded at the finish line of the Boston Marathon. No one has claimed responsibility for what authorities have labeled a "terrorist" attack. Some 175 people were injured, and three people, including an 8-year-old boy, were killed.
In the days since, local state and federal authorities have sought clues to determine who was responsible for the attack. Authorities have determined that at least one bomb was likely built from a pressure cooker, filled with gunpowder as well as nails and BBs to inflict damage.
Many of the injured received wounds to their lower bodies, which caused the loss of feet and legs.
The three dead have been identified as: