KILLER OFFENSIVE  One by one, European leaders are dying by assassination. And each of the victims opposed Russia's attempts to gain increasing power. Determined to stop this wave of terror before it hits American shores, Mack Bolan uses the killers' next attack to flush them out. But these assassins are inhumanly fast, impervious to pain and programmed with cutting-edge combat skills by a hard-line Soviet scientist.   Now Bolan is being shadowed by a ruthless Russian intelligence team racing to bury him along with this rogue military project. To save a summit of world leaders, the Executioner must play two brutal factions against each other...and send the assassins' creator to meet his maker.