Colombian officials fear a wave of terrorist acts has begun in response tothe Jun. 9 arrest of Cali cocaine cartel leader Gilberto Rodriguez Orejuela. A bomb explosion in the national congress building in Bogota late yesterday injured two and sent legislators scampering for exits. Officials theorize that the Cali cartel, which has long preferred bribery to violence as a means of doing business, may be responsible for the four bombs which have exploded in the past week (including one that killed 10 and injured 200). Several top government officials have received death threats. Police also believe Tuesday's killing of Jose Mardoqueo Cuellar Camelo, head of counter-intelligence at the Colombian equivalent of the FBI, was also the work of the cartel.