The emerging portrait of the brothers Tsarnaev, deceased Tamerlan, 26, and Dzhokhar, 19, both implicated in a bomb attack at the Boston Marathon, is one that describes a pair of homegrown American jihadis, says the Christian Science Monitor. There have been 63 homegrown violent jihadist plots or attacks in the U.S. since Sept. 11, 2001, the Congressional Research Service reported in January. Two-thirds of those were uncovered or occurred between April 2009 and December 2012. “Most of the 2009-2012 homegrown plots likely reflect a trend in jihadist terrorist activity away from schemes directed by core members of significant terrorist groups such as Al Qaeda,” the report said. There is serious disagreement about the spike in home-grown jihadi activity. Are the Tsarnaev brothers part of a dangerous upswing in homegrown American jihadism since 2009 – or the rare exception in a vastly diminished receding threat? “It does seem to reinforce the overall pattern, the spike that we've seen since 2009,” says Jarret Brachman, former director of research at the Combating Terrorism Center at West Point. David Schanzer of the Triangle Center of Terrorism and Homeland Security in Durham, N.C., says, “There was a big spike in 2009 and 2010, but our data show that Muslim-American terrorism is declining.”