attacks. booker also goes by the name muhammad abdallah hasan. the fbi says he wanted to carry out friday's attack for isis. two undercover fbi informants helped orchestrate a sting operation, helping him buy components what he thought were explosives. booker was interviewed last year by the fbi about the facebook posts. one read "i will soon be leaving you forever. so goodbye. i'm going to wage jihad in hopes i die." the fbi says he told agents he wanted to carry out an inside terrorist attack like the one on ft. hood in 2009 that killed 13 people. >> thanks so much evan perez. and according to reports, a muslim muslim cleric says john booker was mentally ill and was acting strangely days before his arrest. this is the 21st terror related arrest on u.s. soil this year. joining me now, lieutenant general mark hurling, cnn military analyst. okay 21 arrests. that's pretty significant. that's up to john booker. now i wonder whether this