Investigators say 34-year-old, Aaron Alexis, is responsible for killing at least a dozen people, and injuring others, Monday morning at Navy Yard in Washington, DC.
Alexis was discharged the from the Navy in 2011.
Why did he do it? Was he acting alone? Those are the questions the FBI is now looking to answer.
"No piece of information is too small. We are looking to learn everything we can about his recent movements, his contacts and his associates," Assistant Director of FBI Washington Field Office, Valerie Parlav."
In Erie, former FBI agent, and founder of the Institute for Intelligence Studies at Mercyhurst University, Bob Heibel, is weighing in. He says the FBI and other law enforcement agencies in DC, are on top of this case.
"You know what happened with Boston, and how quickly they got that," said Heibel. "You can bet that they'll be going after video cameras, collecting all the resources out there."
Heibel spent more than 20 years in the FBI, dealing with cases of counter-terrorism. At this point, investigators are not ruling out terrorism. With it being this early in the investigation, Heibel says that's a good move.
"The federal government represents a target of choice to many people. There's also a target of opportunity. It's certainly troubling and if it is an act of terrorists then it's something that we have been expecting, haven't we?"
**UPDATE** Since this story was posted, authorities say they now believe that Alexis acted alone and was not part of an organized terror attack.
While the investigation has just begun, Heibel knows from his years in the FBI, even though it may take time, those questions of motive will be answered.
"Identifying the root cause for this, it will be discovered. We will know."
Heibel called this "a case in progress" and with his experience in the FBI, he said we will know the answer to those questions in the coming days.