Captain America #228 Whitman

"A Serpent Lurks Below" Captain America broods at Avengers Mansion until Iron Man gives him a pep talk; After saving a boy from being hit by a truck, Cap goes to SHIELD's New York HQ to look for the missing Falcon; He defeats a SHIELD robot and finds the base deserted. Jasper Sitwell radios in and tells Cap that SHIELD has abandoned the base for security reasons and that it's due for destruction in fifteen minutes; Sitwell connects Cap with the SHIELD Super-Agents in Los Angeles, who report that Falcon's been missing for days; Blue Streak explains that Falcon is looking for someone in trouble named Jim; Constrictor, a costumed assassin working for the Corporation, ambushes Cap and reveals the SHIELD Super-Agents have a Corporation mole in their ranks.