We need more concealed carry, not more gun control

Had anyone been carrying at San Bernardino they could have shot both terrorists long before they killed 14 people and wounded 21.  Far as I am concerned one answer to terrorist shooters (and any other kind of shooter) is to have a gun on you, and return fire.   The other answer is to have enough intelligence to detect and arrest them before they strike.
   Speaking of which, the TV news this morning claims the San Bernardino shooter was in contact with "a known ISIS recruiter" located in Minnesota.  My question is, why is a "known ISIS recruiter" running around loose?  He ought to be in jail, ASAP.  Why wasn't he?