The threat of home-grown terror attacks remains a top US concern a decade
The threat of home-grown terror attacks remains a top US concern a decade after 9/11 amid a series of recent arrests, but some experts believe the problem is being over-blown.
Washington has made it a priority to track down "lone wolf" terror suspects who act alone without links or support from a wider group, such as the Al-Qaeda militant group which carried out the September 11, 2001 attacks in which almost 3,000 people were killed on US soil.
"The most likely scenario that we have to guard against right now ends up being more of a lone wolf operation than a large, well coordinated terrorist attack," said President Barack Obama earlier this year.
US Department of Justice spokesman Dean Boyd said several dozen suspected homegrown violent extremists have been arrested and charged in the United States since 2009.
"We have seen a dramatic increase of homegrown violent extremists, including US citizens and residents inspired by extremist ideology, plotting attacks against targets in the United States," he said.
In one of the most high-profile cases a US woman named Colleen LaRose, nicknamed "Jihad Jane," pleaded guilty this year to plotting attacks abroad.
The blonde American allegedly contacted foreign terrorists who recruited her to kill a Swedish cartoonist who had illustrated the Prophet Mohammed with a dog's body.
And then just weeks ago Oscar Ramiro Ortega-Hernandez, a 21 year-old from Idaho, was arrested for allegedly firing shots at the White House.
He was charged with attempting to assassinate Obama.
But Michael German, a former FBI counterterrorism agent who handles national security issues at the American Civil Liberties Union (ACLU), said the "lone wolf" threat may have been overstated.
"The numbers remain relatively small," said German, author of the book "Thinking Like a Terrorist."
"It's not a non-existent problem, but certainly not something new and growing," German told AFP.
At issue also is the use of informants and whether some of those eventually charged were drawn into schemes devised and laid out by US law enforcement agents, which were never going to be implemented.
Earlier this year Rezwan Ferdaus, 26, pleaded not guilty in a Massachusetts court to planning an aerial bomb attack against sites in Washington -- the latest in a string of US citizens caught through FBI sting operations.
If agents and informants are "involved providing the means to accomplish the plot and that obviously this person hasn't done anything prior the government's involvement, it's hard to know what this person would have done," said German.
"I am not sure that it counts as a terrorist if the government provides the means and the opportunity."
Since September 11, terror attacks have killed 17 people in isolated incidents in the United States, including 13 who died in a 2009 military base shooting.
The concept of US-grown lone attackers has gained growing traction since Army psychiatrist Nidal Malik Hassan opened fire in Fort Hood, Texas, amid allegations he had contacts with radical US-born cleric Anwar al-Awlaqi in Yemen.
"Although many of the recent plots may be smaller in scale than the 9/111 attacks, they can still prove extremely deadly as evidenced by the 2009 shootings at Fort Hood, Texas," Boyd said.
America was on heightened alert after the killing of Al-Qaeda leader Osama bin Laden in May, and during the 10th anniversary of September 11.
But no attack came, highlighting for terrorism expert J.M. Berger the lack of organization by "lone wolf" terrorists.
"They just don't act strategically, they just randomly pick up targets" said Berger, the author of "Jihad Joe: Americans Who Go To War In The Name of Islam."
He told AFP Al-Qaeda tells them "not to talk to anybody, but they always do... that's why these people get caught. They're always caught."
Department of Justice officials warn threats from "lone wolves" are hard to detect in part because they do not communicate with foreign organizations.
But German is not convinced by the argument.
"This rhetoric is more an attempt to identify an emerging threat to justify continuing surveillance and other counterterrorism programs as the former group of Al-Qaeda is downgraded as a threat," he said.
Berger, meanwhile, said the Federal Bureau of Investigation is "spending a lot of money, time, and energy on people that are not very credible."
One such case may be that of Jose Pimentel, 27, an unemployed Dominican-born US citizen arrested last month in New York for allegedly plotting to build home-made pipe bombs to kill government workers and returning US troops.
He has yet to be formally charged, and the FBI has reportedly refused to handle the case amid huge questions over how solid the evidence is against him.
"In the near future, there must be a serious thought about how these cases are handled," said Berger, adding some of the cases did not justify the means the FBI devotes to them.