A vocal opponent to Venezuelan President Hugo Chávez is still missing, and the details of his disappearance remain sketchy.

BY PHIL GUNSON
Special to The Herald

CARACAS - The whereabouts of dissident Venezuelan Air Force Col. Silvino Bustillos remained a mystery Saturday, a week after he was allegedly arrested at his home in Caracas by a military intelligence unit.

Four years ago, Bustillos, now a director of a radical opposition group called the Democratic Bloc, was one of the first military officers to break publicly with President Hugo Chávez.

He disappeared last Sunday, while local and regional elections were taking place in Venezuela. Government officials deny that he is in custody, and relatives and colleagues say they fear for his safety.

''We have not the slightest doubt that this kidnap is the work of the regime,'' the Bloc said in a statement. ``We therefore hold Hugo Chávez directly responsible for what may happen to Bustillos, and we demand his prompt reappearance.''

After casting his vote early Sunday, colleagues and family members say, Bustillos was pursued by a group of men on motorcycles and eventually sought refuge at police headquarters in the opposition-run municipality of Baruta.

Bloc officials said that a man who identified himself as Lt. Danny Alfredo Daniels, of the National Guard's intelligence division, attempted to arrest him at the police station. However, in the absence of a warrant, the Baruta police refused to hand him over.

Close to 10:20 a.m., the same group allegedly arrived at Bustillos' residence, where he is said to have been alone, but details of what exactly happened there are hazy. Since then, there has been no word from the colonel, according to Alejandro Peña Esclusa, secretary-general of the Democratic Bloc.

''There's a black hole there,'' Peña acknowledged. ''Maybe Silvino escaped.'' He added, however, that the fact that the colonel had not subsequently made contact with his family led them to fear the worst.

A National Guard intelligence officer reached by telephone said the unit's alleged involvement in the disappearance was ''media propaganda,'' spread by people who ``only want to slander the institution.''

Asked if a Lt. Daniels was attached to the intelligence division, he said, ''There is information that cannot be given over the telephone,'' adding, ``I can assure you that we had nothing to do with [the kidnap].''

The government has been tight-lipped about the disappearance, although the public prosecutor's office has assigned a prosecutor to the case and Parliament has set up a bipartisan commission of inquiry. Such commissions have a history of failure.

Bustillos is a former military judge. After a failed coup against Chávez in April, 2002, he was one of three officers who sought asylum in the United States. He returned later to participate in opposition activities.