When reports surfaced recently implying the CIA was behind the flood of cocaine into black neighborhoods of Los Angeles that ignited the 1980s crack epidemic, Donald Griffin was not surprised.

"It's something that has been happening for a long time," said Griffin, an African American who owns two barber shops in Baltimore. "I don't think it's anything new."

Neither the shortage of factual substantiation for the reports, published in August by the San Jose Mercury News, nor denials by government officials have had an impact on Griffin. In the African American community the allegations have hit a nerve, highlighting an inclination, born of bitter history and captured in polls, to accept as fact unsubstantiated reports or rumors about conspiracies targeting blacks.

"Over generations there has been a repeated demonstration that there is a basis in the black community for a feeling of attack, a feeling of harassment," said Yvonne Scruggs, executive director of the Washington-based Black Leadership Forum.

Significant numbers of African Americans, for instance, believe the government deliberately makes drugs easily available in their communities, introduced the AIDS epidemic to harm blacks and unfairly targets black elected officials for criminal prosecution, according to public opinion polls.

Many blacks have stopped buying certain soft drinks and fast foods after hearing rumors, fully believed by some, that the foods and beverages contained secret ingredients designed to sterilize black men.

Some black leaders have fed these fears. Nation of Islam leader Louis Farrakhan, for instance, has long blamed the drug epidemic on the government and promoted the theory that AIDS is part of a government plot.

Conspiracy fears involving various arms of the federal government crop up all across America, from far-right militia groups to leftist fringe groups. And polls have shown large numbers of people view the federal government as a threat to their rights and freedoms. But these suspicions run much deeper among blacks, for whom, analysts say, the widespread distrust of the government dates to the legal sanctioning of slavery and has been kept alive by more than a few shreds of evidence.

Among the cases cited most frequently to explain those fears are disclosures that the FBI spied on civil rights leaders, including Martin Luther King Jr., and infiltrated black militant groups in the 1960s in an effort to foment division. For years, many southern police departments were suspected of having ties to the Ku Klux Klan, a view sharpened by the cross burnings and other racist attacks on blacks during the civil rights era that often went unpunished.

Many African Americans in the District point to the 1990 FBI sting that caught Mayor Marion Barry smoking crack cocaine given to him by a former lover as an example of authorities going too far to bring down a black elected official.

Also, black leaders and academics cite the infamous Tuskegee experiment that ran for 40 years until 1972 and followed the progress of syphilis in 399 mostly uneducated black men who were left untreated -- contrary to their belief -- so that government researchers could track the natural course of the disease.

"It is not at all astonishing that people feel this way. It is just a continuation of what people have observed through the years," said Patricia A. Turner, a professor at the University of California-Davis and author of a book about rumor in African American culture.

Often, the history of victimization of black people allows myth -- and, at times, outright paranoia -- to flourish.

Many African Americans, for instance, believe that Charles Drew, the black Washington physician whose pioneering work with blood plasma saved thousands of lives, died after a car accident in 1950 because he was denied treatment at a whites-only hospital. But Drew actually died as white surgeons who happened to recognize him worked to save his life, according to a Drew biography. For African Americans, though, the myth fits a larger historical reality: that a man who had benefited medicine for all races died because of anti-black attitudes.

Sales of Tropical Fantasy, a soda produced by a firm that employs a large percentage of minorities in a depressed section of Brooklyn, N.Y., plummeted several years ago after mysterious leaflets appeared in black neighborhoods warning that the beverage was manufactured by the Ku Klux Klan and contained stimulants to sterilize black men.

Investigations found the claims to be as preposterous as they appeared. But sales recovered only after an extensive public relations campaign that included then-New York City Mayor David N. Dinkins, who is black, drinking a bottle of the soda for television news cameras. Similar unfounded rumors about Klan involvement periodically have plagued the Church's Fried Chicken chain and Snapple soft drinks.

Despite the long history of drug and other rumors in black communities, nothing has provoked such widespread interest and outrage as the Mercury News series about cocaine sales and the CIA. It has been seized upon by black leaders, provided a constant topic for black radio talk shows and been ballyhooed in local black newspapers across the country. The newspaper sent the stories out to African American opinion-makers and has put the articles on its Internet web site, where they have been widely read.

While the stories only implied a CIA link, they did echo credible evidence examined, but never fully resolved, by a Senate committee in the late 1980s of drug dealing by CIA-backed rebels seeking to overthrow the former leftist government of Nicaragua. The notion that the government -- or some powerful, unseen hand -- is involved in drugs fits the daily reality of many African Americans. Griffin, for instance, said that drugs are plentiful in neighborhoods that often are devoid of supermarkets and banks, and he has no doubt the government could do something about that if it wanted to.

"If you are going to advocate say no to drugs,' then do something about it," he said. ". . . If they put their mind to it, it could be stopped."

Whispers of a government conspiracy to dump drugs in black neighborhoods go back at least to the Vietnam War years. Then, the rumor was that heroin was promoted to squelch rising black militancy across the nation. No proof was ever presented, but that hardly mattered.

"I think these things are believed for a couple of reasons," said Jennifer L. Hochschild, a professor of politics and public affairs at Princeton University. "One, there is some real evidence of some of them. . . . Also, these things are taken to be illustrations of racism that blacks know to be true, but find it hard demonstrating."

The latest reports have been denied by the director of the CIA, who said the agency and its operatives had nothing to do with the spread of crack. He has asked the agency's independent inspector general to investigate the matter. House Speaker Newt Gingrich (R-Ga.) and Attorney General Janet Reno also have promised investigations.

But the denials have not cooled the furor over the stories, which also is being fanned by seasoned conspiracy theorists, from political extremist Lyndon LaRouche to activist Dick Gregory.

Gregory -- who has blamed the King assassination on a tangled government conspiracy and attributed the string of black child murders that baffled Atlanta authorities before a black record promoter was arrested in 1981 to secret federal interferon experiments -- has been arrested in protests at the CIA and the Drug Enforcement Administration.

And Gregory said that is only beginning. "We're talking about demonstrations across this country," he said at a recent news conference. "Nothing in the history of this planet is as vile as what we're about to uncover. As bad as slavery was, white folks never accused us of jumping on the boat." But, he said, black people have been blamed for the scourge of drugs.

But deep concern over the CIA drug allegations is coming from more circumspect quarters as well.

Jesse L. Jackson is one of many African American leaders who have called for an investigation of the allegations raised in the Mercury News articles: "We must leave no stone unturned to either end the rumor or capture the culprits."

He said the idea that the CIA may have abetted drug dealing in the black community is "painful but believable." He said both the historical and "circumstantial" evidence leave him no other choice.

Joe Madison, an NAACP national board member, has dedicated his Washington talk show to the issue and has held news conferences to bring the issue into the national spotlight. He also has been arrested in protests staged in reaction to the reports.

Baltimore Mayor Kurt L. Schmoke (D), a former federal and state prosecutor, fired off a series of letters to congressional leaders and fellow mayors asking for support in pressing for a thorough congressional investigation.

As is the case in many largely poor, black communities, Baltimore has been hard hit by drugs: An estimated one out of 14 residents in the city is an addict and some 56 percent of the city's young black males are in jail, named in warrants or on probation or parole -- mostly as a result of drug-related charges.

Civil rights leader Joseph Lowery, attending one of Madison's news conferences, also demanded an investigation. "We have never stopped believing for a moment that there was not some government complicity in the assassination of Martin Luther King Jr.," he said. "This is a continuation of government involvement in dastardly deeds."

Even if a major investigation into the allegations is done, it is unlikely to quell the certainty among many African Americans that the government played a role in bringing the crack epidemic to black communities. "Who in the world in the CIA organization is going to stand up and testify that this is true?" Griffin said. "I think it's a joke. I think the government will very well try to cover up the situation." CAPTION: Easy to Believe: Baltimore barber shop owner Donald Griffin, above, was not surprised by the reports suggesting a CIA link to cocaine trafficking. CAPTION: Former Drug Enforcement Administration agent Celerino Castillo III talks about the allegations. CAPTION: Activist Dick Gregory has been arrested in protests at the CIA. CAPTION: Jesse L. Jackson: "We must leave no stone unturned."