Here’s a general timeline of events, working from latest to the first at 3:04 am EST:
7:57 p.m. Doctors are “pulling ball bearings out of people in the emergency room,” a terrorism expert briefed on the investigation told CNN’s Deborah Feyerick.
The same source said the blasts resulted in at least 10 lost limbs.
7:43 p.m. An 8-year-old boy was among those killed, a state law enforcement source said, according to CNN’s John King.
7:38 p.m. At least 132 people – including eight children – have been injured in the bombings, according to Boston-area hospitals. Boston police earlier said that two people were killed.
At least 17 of the injured are in critical condition, and at least 25 are in serious condition, area hospitals said.
7:08 p.m. A witness, Marilyn Miller, told CNN that she was about 30 feet away from the first bomb when it went off. The second bomb came about 12 seconds after and about 50 to 100 yards away from the first, according to authorities and an analysis of video from the site.
Miller was waiting for a runner who, it turns out, was probably about 10 minutes away from the finish line.
“We saw injuries all around us,” Miller said. Someone was putting pressure on a woman’s neck. “A little boy, his leg was torn up. A woman, (people) were (shouting), ‘Critical, critical, get out of out way!'”
6:57 p.m. John Boehner tweets: The House observed a moment of silence tonight out of respect for the victims of the Boston Marathon tragedy.
6:51 p.m. At least 110 people have been injured in the bombings, according to Boston-area hospitals.
6:49 p.m. Boston cell phone services were overloaded in the wake of the blast, slowing the city’s network dramatically and hampering the investigation in the early going, federal law enforcement officials told CNN.
Unconfirmed rumors began circulating on social media and elsewhere that law enforcement had shut down cell service to prevent more explosives from being detonated remotely. But mobile companies were saying that was never the case, CNN’s Doug Gross reports.
“Verizon Wireless has not been asked by any government agency to turn down its wireless service,” a spokesman for that company told CNN. “Any reports to that effect are inaccurate.”
In other media reports, Sprint similarly denied being asked to shut down service.
On line, Bostonians were being encouraged to stay off of their mobile phones except for emergencies and even open up their wireless connections to help take the load off of the cellular data network.
“If you live or run a business in #Boston near bombsite pleae open your wifi for people to use,” tweeted Disaster Tech Lab, an Irish nonprofit dedicated to providing technology to assist in emergency situations.
6:15 p.m. CNN: 80 hurt in explosions at Boston Marathon.
6:13 p.m. President Obama: “The American people will say a prayer for Boston tonight, and Michelle and I send out deepest thoughts and prayers to the victims. We will find out who did this and why they did this and we will hold them accountable.”
5:45 p.m. The AP reports that President Barack Obama will speak from the White House this evening on the events in Boston at 6:10 p.m.
5:31 p.m. The AP reports more than 50 people have been injured in the two explosions near the finish line.
5:26 p.m. The Secret Service says it has expanded its security perimeter at the White House following the events at the Boston Marathon.
Spokesman Ed Donovan said it is not unusual to expand or contract the security perimeters. Shortly after the explosions, Secret Service shut down Pennsylvania Avenue outside the White House.
5:21 p.m. Attorney General Eric Holder has directed full resources of the Justice Department be deployed to investigate the bombs that exploded at the marathon.
5:12 p.m. There has been no immediate word on the motive or person responsible for the attacks. According to local hospitals, at least eight of the wounded are in critical condition.
5:06 p.m. The AP reports the total numbers of casualties from the first two blasts is not known.
4:59 p.m. Boston police say there has been a third explosion in the city. Police Commissioner Edward Davis says authorities are not certain that the explosion at the JFK Library was related to the other blasts, but they are treating them as if they are.
There are no injuries stemming from the third explosion.
4:55 p.m. A law enforcement official told the AP cellphone service has been shut down in the Boston area to prevent any potential remote detonations of explosives. The AP still reports two dead and 23 injured.
4:41 p.m. One runner, a Rhode Island state trooper, said the blasts tore limbs off dozens of people.
4:34 p.m. British police are reviewing security plans for Sunday’s London Marathon.
4.31 p.m. President Barack Obama called Boston’s mayor and the Massachusetts governor to express his concern and condolences for those injured in the incident.
4:29 p.m. The Federal Aviation Administration is warning pilots of a no-fly zone over the site of the explosions.
4:24 Two more explosives were found in the area near the Boston Marathon, officers worked on dismantling them.
4:08 p.m. Boston Police Department reported there were two dead and 22 injured in the two explosions near the finish line.
4:04 p.m. Boston Marathon organizers stated the explosions were caused by bombs.
3:04 p.m. Two explosions at the finish line of the Boston Marathon resulted in injuries.
More soon.
Zennie Abraham | Zennie Abraham or “Zennie62” is the founder of Zennie62Media which consists of zennie62blog.com and a multimedia blog news aggregator and video network, and 78-blog network, with social media and content development services and consulting. Zennie is a pioneer video blogger, YouTube Partner, social media practitioner, game developer, and pundit. Note: news aggregator content does not reflect the personal views of Mr. Abraham.