BY GLENN GARVIN

When Ed Schumacher spotted the line of Cuban refugees climbing aboard the boat in Mariel Harbor -- some shuffling vacantly, others caressing lurid tattoos of daggers and skulls -- he knew he was onto a good story. He didn't know he was going to rewrite history.

''I thought I certainly had found something a bit scandalous,'' recalls Schumacher, an incognito New York Times reporter aboard a fishing boat, trying to take notes inconspicuously as he covered the 1980 boatlift of refugees from Mariel to Key West.

''But what effect it would have, I had no idea. I'd like to say I was so wise, but I wasn't.''

The story Schumacher filed that afternoon ran on the Times' front page the next day under the headline Retarded People and Criminals Are Included in Cuban Exodus.

It would single-handedly transform what had been sympathetic and even admiring press coverage of the 125,000 refugees fleeing Cuba through Mariel into the media equivalent of a lynch mob, crafting a stereotype of cocaine-drenched, chainsaw-wielding psychotics that would fascinate Hollywood, freak out cops and terrify most Americans for years to come.

And the fallout would haunt not only the Mariel Cubans, but Miami itself for decades.

'The news media tended to focus on the 'undesireables' that the Castro government forced onto the boats,'' says Maria C. Garcia, author of Havana USA, a history of Florida's Cuban exile community.

''The majority of those who arrived in the U.S. were decent, hard-working folks, who simply wanted to be reunited with their family members, or have new opportunities; but their stories were buried in larger stories with very sensationalistic headlines.''

Schumacher couldn't possibly have foreseen that when he sidled up to the 70-foot fishing boat Valley Chief to chat with the refugees. Nonetheless, he quickly found the first evidence to support a rumor that had been popping up in the American press for two weeks: that among the tens of thousands of refugees boarding vessels in Mariel, Fidel Castro was systematically concealing prison inmates and mental patients.

''I just happened to be at the dock when that boat was loaded up,'' says Schumacher, who for two weeks had been posing as a Cuban in search of his family as he covertly filed stories back to the Times. ''You could see these poor people -- they were clearly insane asylum cases, a lot of them, seriously schizophrenic and retarded.

''And mixed throughout them were these tough-looking guys with tattoos. Now everybody's got a tattoo, but it was not so common then.''

The refugees made little attempt to hide where they came from. 'Some of them would say right out, 'I got out of jail to come over here,' '' remembers Schumacher. 'Some tried to hide it, to claim they had been at the Peruvian embassy [where 10,000 Cubans had demanded asylum the month before, the incident that triggered the boatlift]. But then the guy beside him would say, 'Bull----, he came from the same prison I did.' ''

Schumacher's story the next day was restrained. He reported that several hundred mental patients and prison inmates had been loaded aboard two vessels bound for Key West and, adding details gathered by a Times reporter in Havana, called it part of 'a major effort, discussed openly by Cuban officials, to rid the country of criminals, mentally retarded people, delinquents and others the government calls 'scum' by sending them to the United States.''

But he made no attempt to characterize the entire boatlift as a floating jailbreak. Many of the prison inmates aboard the Valley Chief wouldn't be considered criminals in most countries, Schumacher wrote. One man he interviewed had been jailed for being jobless, another for a joyride in a government jeep. Other crimes ''were more politically than criminally motivated,'' the story added.

'REJECTED'

MEDIA'S PORTRAIT OF REFUGEES CHANGED

Those niceties, however, would quickly be lost, not only on the rest of the U.S. press corps but on American officials back home.

''The Mariel refugees got the shorter end of the deal in every sense,'' declares Felix Masud-Piloto, a DePaul University historian and author of the forthcoming book Contesting Asylum: Cuba, Peru, the U.S. and the Mariel Boatlift of 1990. ''They were rejected by everybody -- the attorney general, the Justice Department, the media, Miami itself.''

Before Schumacher's story on May 11, American press coverage of the boatlift -- although not ignoring the logistical headaches and political snarls -- had painted a sympathetic picture of the refugee themselves. Story after story mentioned refugees braving Castro-backed mobs to escape, leaping from boats to kiss the docks at Key West or joyously celebrating public Masses for the first time once safely ashore in Florida.

Of course, Cuba's government-controlled press had from the start referred to the refugees as escoria and gusanos (scum and worms) and proclaimed they were responsible for more than half of the island's crime. And a handful of U.S. officials -- notably Attorney General William H. Webster and U.S. Rep. Elizabeth Holzman of New York -- had voiced suspicions that Castro was slipping criminals and crazy people into the wave of refugees.

But that claim was viewed skeptically by many in the press. Just a week before Schumacher's story appeared, the Washington Post reporter covering the boatlift, Ward Sinclair, had written a front-page commentary that dismissed the warnings as so much ''muttering.''

''They are human beings who worry about feeding their children, who don't want Big Brother thinking for them, who don't want neighbors spying on them, who want to eat, sleep work and breathe as reasonably free people,'' Sinclair wrote of the refugees.

But Schumacher's story -- which ran the same morning that a record 4,588 refugees arrived at Key West in a single day -- changed everything. In a matter of days, freedom-loving refugees had turned into predatory and perverted Marielitos in the media's eyes.

On May 16, New York Times columnist James Reston wrote that Castro had ''mocked the authority of the White House'' by unloading ''his criminals and mental cripples'' on the United States. On the same day, The Times' editorial page, which only 12 days earlier had chided the Carter administration to ''take the refugees, and stop being so grudging about it,'' reversed itself and called for tight enforcement of immigration law. Castro ''mocks the generosity of the United States by dumping criminals, even leprosy patients, into the boats,'' a Times editorial blustered.

Assessing the criminality of the day's arrivals became as routine as reporting the weather. ''Fewer prisoners, prostitutes and pimps are showing up among the Cuban refugees landing in South Florida,'' The Post wrote.

Eventually even the slightest negative detail about the Marielitos was enough to warrant a separate story. The Washington Post reported on Aug. 14 that 10 refugees had been admitted to St. Elizabeth's mental hospital. The only other admission to St. Elizabeth's that the Post considered newsworthy enough to publish about in 1980: country singer Tammy Wynette.

LINKED TO CRIME

TIMES STORY QUOTES DAMNING STATISTICS

A Dec. 18, 1980, Times story quoted a litany of damning Miami crime statistics -- homicide up 103 percent, robbery up 124 percent, assault up 109 percent -- without noting they were artificially inflated by the wave of murder and looting that accompanied the McDuffie riots, which broke out in May 1980 after four white Miami cops were acquitted by an all-white Tampa jury in the beating death of black motorcyclist Arthur McDuffie.

In fact, Dade County crime began increasing steadily and sharply in 1970 -- in large part due to the drug trade mayhem and so-called cocaine cowboys of the Colombia cartels. This was long before the Mariel refugees arrived.

The 515 homicides in Dade County made 1980 the most murderous year in history (as 1979 had been before that). Scholars still puzzle over the exact causes of the 62 percent year-over-year increase. Criminologist William Wilbanks, who studied the police report of every murder in the county in 1980, concluded that Mariel refugees were responsible for only a quarter of the increase.

''Crime was going up, yes, but it had little to do with Marielitos and a lot to do with drugs and other things,'' says Benigno Aguirre, a sociologist at the University of Delaware's Disaster Research Center.

The press rarely provided context in reporting the criminality of the Mariel refugees. Many of the reported ''criminals'' were fakers. One way to get permission to leave Cuba during the boatlift was to sign what the Castro regime described as a carta de escoria (literally, scum-letter) confessing to a criminal record or sexual deviance. Thousands of Cubans signed them routinely without ever dreaming they would be taken literally by immigration officials in the United States.

And if a Mariel refugee had really been in prison, it was usually not for anything that would be considered a crime in most countries. Their rap sheets included jail time for slaughtering a cow without government permission, refusing to join the Communist Party, not having a job, homosexuality and violation of the Castro regime's favorite catch-all -- the ley de peligrosidad, the law of dangerousness.

''The law of dangerousness said, essentially, that you could be picked up on a street corner for the way you looked,'' explains historian Masud-Piloto. ''If you had long hair and looked like a hippie. Or gay -- there was a lot of repression of gays during that period. Or listening to the Beatles -- the Beatles were banned in Cuba, they were considered subversive musicians.''

When the U.S. screening panels that reviewed the records of the refugees before granting them immigration papers threw out all the cartas de escoria and the bogus political counts, they wound up with 1,306 refugees who had committed crimes serious enough to be confined in minimum-security prisons, and 350 serious felons who were sent to maximum-security prisons in the United States.

That represents about 1.4 percent of the 120,000 refugees the panels screened, compared with the 6 percent of Americans who had committed a felony in 1980, according to FBI crime statistics.

Nonetheless, distorted crime statistics quickly turned into a cottage industry for the news media. By late May, People magazine was quoting a U.S. official who claimed more than 100,000 of the Mariel refugees were criminals.

Predictably, the barrage of negative stories soon turned Americans firmly against the Marielitos. An ABC News poll showed three-quarters of the public thought the Carter administration should never have admitted the refugees, and 57 percent believed they should be kicked back out.

Eventually, the Mariel stereotype extended to Cuban immigrants in general in the public's eye. A 1982 Gallup poll showed Americans ranked the contributions of Cubans last among 15 national and ethnic groups of immigrants.

Not surprisingly, cities from San Diego to Puerto Rico began refusing to accept the Mariel refugees. One state legislator said Marielitos weren't fit to walk the streets of Texas because they ''urinate in public and are prone to masturbation.'' In little Plains, Ga., President Carter's own mother, the folkloric Miz Lillian, regaled reporters: ''I'll tell you the truth, I hope they don't come to Plains.'' Meanwhile, Sen. Donald Stewart of Alabama protested that the refugees were too dangerous even for the maximum-security prison in Talladega.

ERRORS' EFFECT

NATIONAL PUBLICATIONS CONTINUED STEREOTYPE

Journalism is often called the first draft of history, and errors are expected. But in this case, they lasted well into the second, third and fourth drafts, too:

• Time magazine's notorious 1981 cover story titled Paradise Lost? called South Florida ''a region in trouble . . . An epidemic of violent crime, a plague of illicit drugs and a tidal wave of refugees have slammed into South Florida with the destructive power of a hurricane.'' The magazine left little doubt that the first two problems were triggered by the third: ''Marielitos are believed to be responsible for half of all violent crime in Miami.''

• U.S. News & World Report in a 1984 story on Castro's 'Crime Bomb' Inside U.S. called the Mariel refugees ''one of the most despised immigrations in this nation's history . . . Fidel Castro himself called them escoria, scum, and many American who greeted them with open arms now agree with him.'' The story claimed claimed that 10,000 Mariel refugees had been arrested in New York and Miami alone.

• The New York Times Magazine, in a 1987 cover story headlined Can Miami Save Itself? A City Beset by Drugs and Violence, compared Mariel to one of the great catastrophes of all time: ''Miamians speak of 1980 as San Franciscans who survived the great earthquake and fire must have spoken of 1906.''

• In 1987, The New Yorker not only credited Mariel refugees with the invention of the cocaine trade (even though Colombian cocaine cowboys were shooting it out at Dadeland a full year before the boatlift) but accused them of turning Miami into a slaughterhouse: ''The criminals whom Castro chucked out along with the refugees were willing to do anything -- run drugs, steal cars, burn down a house, murder -- and to do it for rock-bottom wages. Everything, including life itself, became too cheap.''

POPULAR CULTURE

'SCARFACE' AN ENDURING MARIEL ARTIFACT

The news stories ultimately echoed their way into popular culture with the TV series Miami Vice (whose creator Anthony Yerkovich called Miami ''a city in which the American Dream had been distilled into something perverse'') and the most enduring Mariel artifact of all, the film Scarface, in which Marielito narcotraffickers carved one another up with power tools.

The powerful Scarface imagery in turn was soon cited in scholarly criminology journals as if it were fact, completing the cycle of fiction into fact. Historian Mark Dow, the author of American Gulag: Inside U.S. Immigration Prisons, says Scarface has been so destructive that director Brian DePalma, producer Martin Bregman and star Al Pacino should be punished.

''You know how criminals are prohibited in some states from profiting through books or movies about their crimes?'' says Dow. ''Well, Pacino, DePalma and Bregman should donate the Scarface profits to finance housing and job counseling/training for all those they helped keep behind bars.''

Herald researchers Elisabeth Donovan and Monika Leal contributed to this article.