While officials are still investigating who was behind the deadly bombings at the Boston Marathon, President Obama made it clear on Tuesday that authorities are still unclear whether domestic or foreign actors are responsible for the attack.
But one message from domestic terrorism experts is clear: Most of the evidence points against an antigovernment group being responsible for the attack. Several militia groups, who fiercely and sometimes violently fight to keep their Second Amendment rights, have come out against the bombings in Boston.
While some of the factors surrounding the Boston bombings could point to these groups — a simplistic homemade bomb, causing mass casualties, falling on Tax Day — other factors don't add up. For many of these groups, the date that most matters to them is not Tax Day or Patriots' Day or even Hitler's birthday, but the anniversary of the Waco siege (pictured below). On April 19, 1993, 76 people died when a radical, antigovernment sect's compound in Texas burnt to the ground after days of firefights with federal officials. When Timothy McVeigh bombed the federal building in Oklahoma City in 1995, killing 168 people, it fell on the anniversary of the Waco raid, which he cited as a motivation for the attack.
Other members of antitax groups, who believe in a constitutional right not to pay a federal income tax, have attacked the Internal Revenue Service in previous instances. In February 2010, a man flew a small plane into the IRS building in Austin, Texas, killing himself and one other person.
In Monday's case, though, the target was not a federal building or the IRS. This bombing at the Boston Marathon, experts say, doesn't fit with the previous attacks from Patriot Movement types.
"When you think about it, the target is not clear," said Mark Potok, a senior fellow at the Southern Poverty Law Center. "What the target was not was the government, or the IRS, or a minority group — black people, gay people, Muslims, immigrants, Latinos, and so on. It wasn't targeted at any sort of specific subgroup."
Mark Pitcavage, the director of investigative research for the Anti-Defamation League, agreed, saying this target didn't feel like the work of extreme right-wing terrorists since it had no clear connection to the government.
"The bottom line is that no domestic extremist movement, just based on their ideology alone, would have a huge reason to attack the Boston Marathon," Pitcavage said. "The prominence of the event could cause anybody from a variety of movements to carry out an attack like that."
Instead of the work of organized movements, the attack could have been the work of a single person, either someone motivated by ideology or someone who is clinically insane. Eric Rudolph, an antiabortion and antigay activist, set off bombs at the 1996 Summer Olympic Games in Atlanta that killed three people to promote his ideology.
If a domestic terrorist was involved, experts say it's likely the bomber was a part of a virulently antigovernment, antitax group that fits under the broader Patriot Movement.
People who identify with this movement aren't looking for less government or less taxation; they fundamentally believe the U.S. government has been delegitimized though a slow-boiling, malicious conspiracy. Three sub-movements clearly outline the thinking behind their violence.
Sovereign Citizen Movement: As one of the most antigovernment movements in the U.S., the Sovereign Citizen Movement believes that in the 1800s, a slow-acting conspiracy began to slowly infiltrate the federal government and replace it with an illegitimate, tyrannical government. People who follow this movement say they only owe allegiance to the original government. This movement has been blamed for several acts of violence in recent years, including the killing of two West Memphis, Ark., police officers in May 2010 by a father and son duo. Oklahoma City conspirator Terry Nichols was also a follower of this movement.
Militia Movement: Followers of this movement believe the rest of the world has been taken over by a globalist, one-world conspiracy, known to them as the New World Order. Believing the United States is the last bastion of freedom, followers stock up large amounts of weaponry and ammunition, because they think the government might one day go after their right to bear arms. Many followers of the movement liken themselves to the Minutemen who took arms against the British during the Revolutionary War. Patriots' Day, which commemorates the battles of Lexington and Concord, is an important day on their calendar.
Tax-Protest Movement: Adherents of one of the oldest and most narrow-scoped movements believe they have a constitutional and legal right not to pay income taxes. Believing the government is trying to cover this conspiracy up, followers often participate in tax evasion, tax fraud, and violence directed at the Internal Revenue Service.
The number of antigovernment "Patriot" groups hit an all-time high in 2012 at 1,360, according to the Southern Poverty Law Center. With immigration reform and gun control on President Obama's agenda, the SPLC says the number is likely to increase. This sort of group previously peaked in 1996 to 858 groups, following the 1994 ban on assault rifles and the 1993 Brady Bill, as well as the federal government's violent suppression at Waco, Texas, and Ruby Ridge, Idaho.
Several of the mass shootings that have plagued the country in recent years have been by lone perpetrators with serious mental issues. Lawyers for James Holmes, the man behind the Colorado movie-theater shootings that claimed the lives of 12 people, are attempting to identify him as insane. Officials have also said that the men behind the shootings in Newtown, Conn., and Tucson, Ariz., showed signs of criminal insanity.
All photos are by the Associated Press
CORRECTION: An earlier version of this story misidentified the year of the Oklahoma City bombings.