Since the Sept. 11, 2001, terrorist attacks, homegrown violent extremists have carried out more than 20 attacks in the United States, many of whom were suspects the FBI had previously investigated for possible terrorist links, according to the 47-page report. After these attacks, the FBI reviewed practices in assessing terrorist threats and found instances in which investigators did not sufficiently follow up or closed investigations into people who later carried out deadly attacks.
Even after reviewing its practices, “nearly 40 percent of counterterrorism assessments went unaddressed for 18 months after deficiencies were known to the FBI,” the report said. Continue reading.