Terrorism investigators are looking closely at a trip taken to Jordan by Mohammod Youssuf Abdulazeez to see if he had contact with known terrorists or terrorist sympathizers.

FBI officials say that Abdulazeez spent seven months in Jordan last year, one of several trips he had made to the region over the last few years. He went to Jordan in the last weeks of 2005, in the summer of 2008, the summer of 2010 and during the spring of 2013.  The trips lasted anywhere from two weeks to two months.

Despite the pattern of trips, the FBI admitted Abdulazeez was not on their watch list of possible terrorist sympathizers or operatives.

However, his father had been investigated years prior for giving money to an organization that had suspected connections to terrorists.

Abdulazeez’s attack on two Navy recruiting centers left four Marines dead.  They have been identified as Gunnery Sgt. Thomas Sullivan, of Springfield, Mass., Lance Cpl. Skip “Squire” Wells, of Marietta, Ga., Sgt. Carson Holmquist, of Grantsburg Wisc., and Staff Sgt. David Wyatt, of Chattanooga.

Security experts say that the shooting shows an inherent weakness in recruiting stations for the military.  The locations need to be easily accessible to the public.

“They’re supposed to be convenient; they’re supposed to be easily accessible,” Brian Michael Jenkins, a security expert who is senior adviser to the president of the RAND Corporation, told the New York Times. “They’re virtually no more protected than a shoe store in a shopping mall.”