Paulk was a military policeman. He recalled Fox as a communications officer serving with deployed reservists from Pennsylvania.
"Brad's unit got attached to ours because we didn't have enough manpower at the time," Paulk said. "We trained them up" in military police skills.
Then, in the summer of 2005, they deployed to Fallujah.
"He was a very professional gentleman. He knew how to be a Marine. He conducted himself with great respect," Paulk said. "An all-around good guy."
Based at Camp Fallujah, the men had the risky job of providing convoy security for improvised-explosive device technicians tasked with defusing roadside bombs.
"Outside the wire we would escort those teams and provide security for them," Paulk said. "It could be pretty hairy sometimes."
Several pictures that Paulk uploaded to a memorial website page for Fox show Fox standing near military vehicles bearing signs emblazoned "danger" in English and Arabic.
After the men returned to the U.S. and left the service they did not keep in touch.
"I stumbled onto his Facebook page a few months ago," Paulk said. "I didn't even get a chance to friend-request him."
Paulk learned of his death through a fellow Marine who posted a link to Fox's memorial page.
Contact Michael Matza at 215-854-2541 or mmatza@phillynews.com