Although I'm inclined to think these terrorists are indeed probably Islamic Jihadists, we don't know that for a fact--yet.

This bombing was on Patriot's Day, a day which memorializes the Revolutionary actions at Lexington and Concord. And April 15 is a date with profound tax implication. And there's a lot of hysteria going around now about gun control, abortions, and race conflict. It's pretty obvious there are people in this country psyching themselves up for a Ft. Sumter moment.

It can't be ruled out that this attack was carried out by domestic, perhaps even right-wing, terrorists. In fact, if I'm not mistaken, there have been very few or no successful terrorist attacks in CONUS due to Islamists since 9/11. They have been directed at "the government." There's been a lot of disturbing talk about "2nd amendment solutions" lately. I'm sure you've heard the chatter, "its time to take OUR country back", etcetera, etcetera.

Besides Al-Quaeda and their surrogates, we have other options.

2.1 Animal Liberation Front
2.2 Alpha 66 and Omega 7
2.3 Army of God
2.4 Aryan Nations
2.5 Black Liberation Army
2.6 The Covenant, The Sword, and the Arm of the Lord
2.7 Earth Liberation Front
2.8 Jewish Defense League
2.9 Ku Klux Klan
2.10 May 19th Communist Organization
2.11 The Order
2.12 Phineas Priesthood
2.13 Symbionese Liberation Army
2.14 United Freedom Front
2.15 Weathermen

3 Notable attacks associated with domestic terrorism
3.1 Bombing of Los Angeles Times building
3.2 Wall Street bombing
3.3 Bath, Michigan bombings
3.4 Unabomber attacks
3.5 Attacks by the Jewish Defense League
3.6 Oklahoma City bombing
3.7 Centennial Olympic Park bombing
3.8 2001 anthrax attacks
3.9 Knoxville Unitarian Church shooting
3.10 Murder of George Tiller
3.11 Holocaust Memorial Museum shooting
3.12 Fort Hood shooting
3.13 Austin IRS attack
3.14 Southern California shootings
3.15 2013 Boston Marathon Bombings

http://en.wikipedia.org/wiki/Domestic_terrorism_in_the_United_States