U.S. officials said today that Ernest Bennett, father-in-law of deposed ruler Jean-Claude Duvalier, was the key link here for a drug ring smuggling cocaine from Colombia through Haiti to the United States.

A U.S. official charged, "There are four or five drug rings operating in Haiti, and Bennett was the contact for one of them." He cited evidence gathered by U.S. and Haitian authorities after the fall of the Duvalier government Feb. 7.

However, Police Maj. Carrel Occil, in charge of drug enforcement, said his investigators have not found sufficient hard evidence to prosecute Bennett. "I don't have any proof," Occil said. "I don't have any documents or informers against him."

Diplomats here said that if Bennett can be implicated directly in the drug traffic, it will be easier for the Haitian government to appeal to banking authorities in Switzerland to make public confidential information about Bennett and Duvalier family accounts there.

The accounts, which Haitian officials believe contain at least $370 million, were frozen by Swiss banks in April. Swiss laws protecting depositors' anonymity can be waived if the funds are shown to come from drug smuggling.

Bennett has been in exile since the week before Duvalier's fall and is believed to be traveling in the United States and Europe, U.S. officials said. He was not reached for comment.

U.S. suspicions against Bennett, an official said, began with the Dec. 12 arrest in the southern port of Les Cayes of six people, including two Colombians, caught moving 895 pounds of cocaine. One of those arrested, a Haitian named Marvin Cardozo, was known to be an associate of Bennett, the U.S. official said.

"After Feb. 7, the Haitian authorities told us they were convinced Cardozo was linked to Bennett," the official said.

"That's correct," said John Sutton, a Puerto Rico-based agent for the Drug Enforcement Administration. He said Bennett's links to Cardozo had become "part of an ongoing investigation" into drug transshipment operations through Haiti.

On the afternoon of Feb. 7, only hours after the abrupt departure of Duvalier threw this nation into confusion, senior U.S. diplomats raised the drug enforcement issue in a meeting with high-ranking Haitian Army officers.

The Americans were told to expect much-improved cooperation from Haitian authorities because a "godfather" who had protected cocaine transshipments through Haiti was gone, according to a U.S. official. Several days later the Haitian officers identified the "godfather" as Bennett, the official said.

In the days after Feb. 7, Haitian security forces found more than 200 pounds of cocaine in a medicine storehouse at the Bon Repos Infant-Maternity Hospital just outside Port-au-Prince, U.S. officials confirmed.

The hospital was administered by a foundation run by Michelle Bennett, Duvalier's wife and Bennett's daughter.

Sutton confirmed that Haitian authorities also reported finding smaller amounts of cocaine concealed at an automobile agency owned by Bennett and at one of Duvalier's homes, in the Port-au-Prince suburb of Fermathe Petit Rocher.

Bennett's son, Frantz Bennett, was arrested in 1982 in Puerto Rico on cocaine trafficking charges. He served 2 1/2 years in a south Florida prison. U.S. officials said it is not clear if there is any connection between the alleged drug activities of the father and those of his son.

Haitian and U.S. officials here said cocaine transshipping through Haiti had increased since 1983, when Colombian authorities cracked down on the drug traffic there.

The cocaine is brought by Colombian drug dealers by sea and air to Haiti's southern coasts, then trucked overland to Port-au-Prince, investigators said.

Diplomats here described Bennett as a largely unsuccessful entrepreneur whose business fortunes only began to improve after the 1980 marriage of his daughter to Duvalier, whose family ruled Haiti for almost three decades. He was widely believed to have used his ties to the president to influence his business deals.

Haitian and U.S. authorities said they did not have direct evidence connecting Duvalier to any drug operations.

[The Duvaliers told ABC News correspondent Barbara Walters in an interview broadcast Thursday night that reports they had misused government funds were untrue. "There never was any embezzlement," the former president said, "It's just simply and purely a lie. It is slander."]