These bombing are distinct from the 34 police officers who have been "murdered by domestic right-wing political extremists” since Oklahoma City, according to the  Southern Poverty Law Center. And they do not include the worst gun massacres in the U.S. since then, which include: Littleton, CO in 1999 (15 dead); Blacksburg, VA in 2007 (32 dead); Ft. Hood, TX in 2009 (12 dead); Tuscon, AZ in 2011 (6 dead); Oakland, CA in 2012 (7 dead); Aurora, CO in 2012 (12 dead); and Newtown, CN last December (28 dead). 

On Tuesday, police said that the two bombs that killed three and injured 176 people at Monday’s Boston Marathon was a homemade device—a metal pressure cooker filled with nails, ball bearings, metal shards that were left in duffle bags near the finish line. This is similar to roadside bombs used against U.S. troops in Iraq and Afghanistan, various news organizations reported.

What follows is a list of other domestic bomb attacks and attempts dating back to 1995, with additional details on the types of bombs used.

• Jan. 17, 2011. White supremacist Kevin Harpham put a backpack bomb along a Martin Luther King Day parade route in Spokane, WA., but it was found and disabled. "The pipe bomb was loaded with lead fishing weights coated in rat poison, which can inhibit blood clotting in wounds,” AOL.com reported. Harpham was sentenced to 32 years in prison.

• May 1, 2010. Pakistani immigrant Faisal Shahzad left an explosives-laden SUV in New York’s Times Square. Smoke was seen coming from the car and the bomb was found and disabled. The car was "packed the car with more than 100 pounds of fertilizer, but not the kind that would explode,” ABC-TV reported. Other news reports said he put the fertilizer in pressure-cookers—like the Boston bombs—and used firecrackers as the trigger. Shahzad was taken off a plane by police and was sentenced to life in prison.

• Dec. 25, 2009. A Nigerian, Umar Farouk Abdulmutallab, was subdued by passengers and the crew after trying to blow up a plane in midflight from Paris to Detroit by using plastic explosives hidden in his undergarments. He was sentenced to life in prison.

• Sept. 11, 2001. Four commercial jets were hijacked by 19 al-Qaida militants and used as suicide bombs, destroying New York City's World Trade Center towers, crashing into the Pentagon and into a field in Pennsylvania en route to Washington. Nearly 3,000 people were killed in New York, Washington and Pennsylvania.

• Jan 22, 1998. Theodore Kaczynski, the so-called Unabomber, pleaded guilty in federal court in return for a life sentence without parole. He was responsible for 16 attacks that started in 1978 and lasted until 1995, killing three people and injuring 23 others. His first bombs used smokeless explosive powders, while his later devices were complicated nail-and-splinter-loaded bombs that were made with wooden parts and designed to explode when opened by intended recipients who received them in the mail.

• July 1996 to January 1998. Eric Rudolph, an anti-abortion activist, was responsible for four bombings from 1996-98, all using slightly differing homemade devices. Speaking of the most infamous attack, at Centennial Park in Atlanta, HistoryCommons.org said: