ABC News uncovered exclusive details that reveal Al-Qaeda terrorists were granted refugee status in the United States.
The same terrorists are tied to the deaths of some American soldiers.
"I cried my eyes out when he got killed," said Gus Petaccio. "That's how nice a fellow he was."
Neighbors of one of four Pennsylvania guardsman killed by an Al-Qaeda roadside bomb in 2005 absorbing the news the likely bomb maker had been granted refugee status in 2009 and lived freely in the US for two years.
"Angry yes. It's appalling. It is. People aren't doing the job they are supposed to do to protect the people of this country," said Kevin Kelly.
According to the Brian Ross report, Waad Alwan bragged to an FBI informant that he was responsible for a 2005 blast that killed Specialist Gennaro Pellegrini of Philadelphia along with PFC Nathaniel DeTample, Specialist Francis Straub and Specialist John Kulick, all Pennsylvania guardsman from our area.
Federal authorities say they did not have quite enough evidence to charge them for the guard bomb.
"They certainly feel these two men were responsible that have blood on their hands; the blood from the Pennsylvania National Guardsmen," said ABC Reporter Brian Ross.
Alwan and another Al-Qaeda refugee were later arrested in Kentucky in 2011 and convicted after being caught in a sting to ship weapons to terrorists.
Ross' report says they were allowed in the U.S. despite evidence Iraqi authorities had suspected they were insurgents. But that information apparently never got to U.S agents who did their background checks.
"Just a flawed system the dots were not all connected. They were all there. They could have known it, but they didn't set up the system that way," said Ross.
Two men are in prison, but Ross reports that the FBI is very concerned that there could be dozens of other Al-Qaeda operatives including bomb makers who came into the country under that flawed system.
Ross says there is an ongoing investigation looking for any others.