A list of what we know about the Boston Marathon bombings as of today

Americans are still reeling from yesterday's attack on innocent bystanders at the Boston Marathon. A number of things have been clarified since then, however the important questions of who is responsible for the attack and why remain mysteries.

LOS ANGELES, CA (Catholic Online) - Here's what we know as of mid-day today.

-    An unknown terrorist or terrorists detonated two anti-personnel bombs yesterday, likely hidden in trashcans.

-    The bombs detonated 12 seconds and about 100 yards apart, possibly designed to inflict mass casualties by exploding amongst fleeing people.

-    Three dead, 173 reported injured.

-    Doctors report severe shrapnel wounds. Reports that ball bearings were used in the bombs remain in circulation, but unconfirmed.

-    The youngest victim was an eight year old boy who was waiting to give his father a hug as he finished the race.

-    Doctors and nurses say the injuries were all traumatic with severe shrapnel wounds. Several people lost limbs in the explosions.

-    Many victims have suffered amputations and many others loss of hearing from ruptured eardrums.

-    Sources within the investigation have said the devices were "crude" in terms of construction.

-    Many lives were saved because of the great number of emergency and volunteer personnel on hand for the event. A number of people were seen running towards danger to aid victims.

-    Reports of additional devices have now been confirmed as untrue. There were only two, both detonated.

-    President Obama has refused to call the attack a "terrorist" attack.

-    Several people including Obama aides and leading Democrats have labeled the attack as a "terrorist attack."

-    The bombings occurred on Patriots Day, a state holiday in Massachusetts and tax day in the U.S. fueling speculation the attack was domestic in nature.

-    The nature of the attack with delayed bomb detonations in crowded public spaces is consistent with al Qaeda tactics.

-    A Saudi national, who authorities say was acting suspiciously, has been detained in the hospital by authorities. He reportedly has severe burns. He is 20 or 21 years old and is in the country on a student visa. His apartment has been searched by authorities. No word on what has been discovered.

-    Another man, possibly of Middle-Eastern origin, was photographed being arrested by authorities after the bombing. His identity is unknown but photos suggest he was wearing a shemagh. Other photos suggest he was wearing a white baseball cap with a scarf.

- Authorities are seeking a person who appeared to be watching events from an area rooftop. That person may be of interest.

-    The FBI says Boston is under no further, immediate threat, but vigilance is advised.

Catholic Online will continue to provide coverage and updates as they become available.

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