Blast kills Iran nuclear expert amid ‘covert war’

TEHRAN, Iran — It seemed a clock­work killing: Motor­cy­cle rid­ers flashed by and attached a mag­netic bomb onto a car car­ry­ing a nuclear sci­en­tist work­ing at Iran’s main ura­nium enrich­ment facil­ity. By the time the blast tore apart the sil­ver Peu­geot, the bike was blocks away, weav­ing through Tehran traf­fic after what Iran calls the lat­est strike in an esca­lat­ing covert war.