We turn to the Boston bombings have the latest tonight. ABC news has learned that the Boston Marathon. May not have been the intended target so what was here's ABC's chief investigative correspondent... See More
We turn to the Boston bombings have the latest tonight. ABC news has learned that the Boston Marathon. May not have been the intended target so what was here's ABC's chief investigative correspondent Brian Ross following all the -- Bryant. -- according to a person briefed on the case the surviving brother told the FBI the marathon became the target. Only because it didn't take them as long to build the bombs as they thought it would. And they were eager to attack. The original target was supposed to be a July 4 of -- in Boston. According to the person briefed on the younger -- states the famed Boston Pops concert and fireworks on the -- -- was not specifically. But it is one of the most prominent July 4 events in the country. Broadcast nationally on CBS. The brother also reportedly told the FBI that the bombs were constructed in the Cambridge apartment of his brother -- -- And that they were able to build the bombs from pressure cookers and fireworks quicker than they had expected according to the brother. Eager to use the bombs the Brothers on April 12. Drove around the area and considered attacks on the Boston and Cambridge police departments and only then realized the preparations were being made for the marathon. And settled on that as the target.
This transcript has been automatically generated and may not be 100% accurate.