CARACAS - The many bizarre aspects of the recent arrests of some 80 alleged Colombian mercenaries accused of plotting to kill President Hugo Chávez have sparked deep skepticism and worry among many Venezuelans and foreign diplomats. The concern is that the leftist Chávez will use the case as an excuse to crack down on his nonviolent opponents or block an ongoing attempt to force a recall referendum on his rule. ''I have no doubt at all that this is an invention of the government,'' said former Foreign Minister Simón Alberto Consalvi, part of the opposition that accuses Chávez of leading...