This is a report done by the NYPD in 2007 that seems to cover the Boston Marathon killers quite nicely.

http://smallwarsjournal.com/blog/nyp...megrown-threat

I heard about yesterday on the radio and read it last night. It is extremely good. To do the report no justice it says these guys go through four stages, pre-radicaliztion, self-identification, indoctrination and jihadiztion. Those four stages also involve some generally common patterns, like getting thrown out or leaving a mosque. From the little I know of older brother, things seem to fit.