It Looks Just Like a War Zone

The afternoon was sultry, and along the deserted block of neat brick row houses in the Cobbs Creek section of West Philadelphia, an ominous calm had descended. Suddenly the thwack of rotors broke the silence. A blue-and-white Pennsylvania State Police helicopter arced in low over the roof-line. It made several passes over the street, then hovered 60 ft. above the two-story home at 6221 Osage Avenue.

In the helicopter cabin, Lieut. Frank Powell, chief of Philadelphia's bomb- disposal unit, hefted a canvas satchel holding two 1-lb. tubes filled with a water-based gel explosive. After lighting its 45-sec. fuse, Powell leaned out...