NEW YORK -- The plot as painted by law enforcement officials was cataclysmic: A home-grown Islamic terrorist had in mind detonating fuel storage tanks and pipelines and setting fire to John F. Kennedy International Airport, not to mention a substantial swath of Queens.

"Had the plot been carried out, it could have resulted in unfathomable damage, deaths, and destruction," Roslynn R. Mauskopf, the US attorney in Brooklyn, said in a press release that announced charges against four men. She added at a news conference, "The devastation that would be caused had this plot succeeded are just unthinkable."

Police Commissioner Raymond W. Kelly then stepped to the lectern with a vision only a bit less grim. "Once again, would-be terrorists have put New York City in their crosshairs," he said. Kelly said a disaster had been averted.

But a reading of the criminal complaint filed by the federal authorities against the four defendants in the case -- one of them remained at large yesterday -- suggests a less than mature terror plan, a proposed effort longer on evil intent than on operational capability.

Mauskopf noted in her release that the "public was never at risk" and told reporters that law enforcement "had stopped this plot long before it ever had a chance to be carried out."

At its heart was a 63-year-old retired airport cargo worker, Russell Defreitas, who the complaint says talked of his dreams of inflicting massive harm, but who appeared to possess little money, uncertain training, and no known background in conceptualizing or planning a terror attack.

"Capability low, intent very high," a law enforcement official said of the suspects.

Some law enforcement officials and engineers also dismissed the notion that the alleged plot could have resulted in a catastrophic chain reaction; system safeguards, they said, would have stopped explosions from spreading.

The complaint, filed in US District Court in Brooklyn, also suggests that at least two of the suspects had some ambivalence. They had ties with Jamaat al Muslimeen, a dangerous Islamic group that once engineered a deadly coup attempt in Trinidad and Tobago. The group allegedly had been approached about underwriting a plot.

One of the men was prepared to bomb the airport but leery about killing masses of people, the complaint says. Another dropped out of the alleged plot for a time to tend to his business. In the end, the men decided to stop courting the Islamic group and resolved to shop elsewhere overseas for terror financing.

One defendant, Abdul Kadir, who was arrested in Trinidad, is said to have warned the others that the Islamists in Trinidad "wanted to minimize the killing of innocents such as women and children."

A third suspect, Kareem Ibrahim, 61, was also arrested in Trinidad, and a fourth, Abdel Nur, 57, remained at large.

No one would second-guess the authorities for pursuing and arresting suspected plotters. One of the most enduring lessons that the attacks of Sept. 11 , 2001, have taught prosecutors and FBI agents is the danger of inaction. But as with many post-Sept. 11 terror plots, the line between terrible aspiration and reality can get lost in a murky haze.

In case after case, from what authorities said was a dirty bomber to the Lackawanna Six, federal prosecutors hail arrests of terrorists and disruptions of what they describe as sinister plots. But as these legal cases unfold, the public often is left groping for certainty about the true nature of threats described so graphically by the authorities.

Mauskopf and Kelly declined yesterday to discuss their characterizations of the airport case. Mark J. Mershon, assistant director in charge of the FBI's New York office, also spoke at the press conference, and he said yesterday that his message was very clear:

"I believe I spoke the simple truth at the press conference: the ambitions were horrific, the capacities were very limited, but they kept trying. Their signature was their persistence."

Neal R. Sonnett, a defense lawyer and former federal prosecutor who was chief of the criminal division in the US attorney's office in Miami, congratulated the FBI for fine police work in what was clearly "a prosecutable case." But he said: "There unfortunately has been a tendency to shout too loudly about such cases."

"It has a bit of the gang that couldn't shoot straight to it," he said. "It would have served the federal government well to say that."

A reading of the criminal complaint suggests why prosecutors and FBI agents grew so alarmed as they learned of the suspects' alleged ambitions. In taped statements attributed to Defreitas, he was unequivocal about his desire to kill many thousands of his fellow Americans.

But the same papers give reason for doubt about the competence of the suspects. The details tend to suggest a distance between Defreitas's dream and any nightmarish reality.

© Copyright 2007 Globe Newspaper Company.