One Boston Marathon Bombing Suspect Killed in Shootout with Police

Numerous law enforcement agencies are continuing their search for the second suspect of the Boston Marathon bombings as daylight breaks in the Boston area. Public transportation has been suspended in the Boston metro area as the search for the suspect continues.

ABC News has learned from Boston police that one of the two suspects in Monday's Boston Marathon bombings is dead.

The news comes after a wild shootout between the suspects and police in Watertown, MA early Friday morning, about four miles from the Boston Marathon finish line where three people were killed and more than 170 injured by twin explosions on Monday.

ABC News is reporting that all federal agents in the area reportedly have been dispatched to the crime scene in Watertown.

This latest development in the bombing case unfolded after the fatal shooting in Cambridge Thursday night of a Massachusetts Institute of Technology police officer in an incident that was reportedly related to a carjacking.  At the time, MIT officials told all students to remain inside, describing the situation as “extremely dangerous.”

Not long after the MIT shooting and an ensuing car chase, law enforcement officers descended en masse upon a section of Watertown about two miles from MIT.  Afterward, there were reports of gunfire and explosions.

According to amateur videos and the testimony of at least one eyewitness, two men driving an SUV engaged police in a firefight that also involved the suspect using explosives.

One of the two men, identified Thursday as bombing Suspect 1, was killed while the other, Suspect 2, described as the man in the white cap, sped off in a car. Police say he is armed and extremely dangerous. A police officer was also injured in the gunfight and is listed in critical condition.

Meanwhile, police were checking whether devices left on a street in Watertown where the shoot-out occurred were similar to the pressure-cooker bombs that were used in the marathon attack.

Friday’s development comes after the FBI on Thursday released images of two suspects in last Monday’s bombings, suspects they consider to be "armed and extremely dangerous."

At a Thursday press conference, FBI Special Agent in charge Richard DesLauriers referred to the two men as Suspect 1 and Suspect 2, and said Suspect 2 was spotted dropping a bag before a bomb exploded at the second bomb site. The two men appear to be "associated," DesLauriers said.

The identities of the suspects have not been released by authorities.

Information from ABC News and the Associated Press used in this report