COLUMN ONE : Jet Probe: Real-Life Whodunit : History’s biggest terrorism investigation spanned 40 countries. Two tiny electronics fragments and a diary were the keys to the Pan Am case.

The indictment of two Libyans in the bombing nearly three years ago of Pan American Flight 103 climaxes one of history’s most extraordinary detective stories.

The drama turned on the ability of Scottish authorities to scour 845 square miles of countryside so thoroughly that they found two fragments of electronics equipment--each smaller than a fingernail--and on the capacity of scientific sleuths to track those tiny fragments to the gates of Tripoli.

The story is one of unprecedented international cooperation, with hundreds of investigators combing 40 countries on four continents for pieces of the puzzle: the fragment of circuit board from a Toshiba radio found in Scotland, a tiny piece from a Swiss-made timer that matched devices seized in two African nations, clothing labels from a store on the island of Malta and a mysterious desktop diary.

Stunning new details about the investigation that led from the Scottish village of Lockerbie to Libya emerged from interviews and documents when officials in Washington and Scotland on Thursday announced the indictment of two Libyan intelligence agents.

The details provide a fascinating and unprecedented road map of how masterly police work and intelligence deductions can sometimes surmount seemingly impossible difficulties.

The key breakthrough, the one that transformed nearly three years of investigation from an intelligence case into a criminal indictment, was the diary--the private jottings of one of the Libyan agents, Lamen Khalifa Fhimah. Although Justice Department officials declined to provide details of how they got the diary, its contents provided the names, dates and times essential to bringing the indictment.

“The diary was the pivotal thing in being able to prove to a grand jury and in a courtroom that these were the guys,” said a U.S. counterterrorism specialist. “This is something that differentiates this case from other terrorist actions that remain unsolved.”

Indeed, diary entries describing plans to steal luggage tags for the bomb-laden suitcase and meetings between Fhimah and his alleged accomplice were the glue that cemented together the largest terrorist investigation in history.

It was an investigation that effectively began at 7:03 on the night of Dec. 21, 1988. That was the moment when an on-board explosion scattered the Pan Am 747 into tens of thousands of pieces above Lockerbie, killing all 259 passengers and crew members as well as 11 people on the ground.

By 8 o’clock that night four days before Christmas, Scottish Police Constable John Boyd had summoned all the help he could muster. Soldiers from British military bases were brought by bus, troop carrier and helicopter to the tiny town to join police and volunteers in combing the countryside for pieces of the wreckage.

Even as the troops were en route, a radar beacon was tracking 1,000 of the largest pieces of debris as they rained down across northern Scotland. The jetliner, on its way from London’s Heathrow to New York, had been shattered by an explosion at 31,000 feet. Winds of 140 miles an hour spread wreckage and bodies all the way from the hills around Lockerbie to the North Sea more than 70 miles away.

A 19th-Century stone schoolhouse in Lockerbie was converted into an emergency headquarters. There, in the early days of the laborious effort, the chief Scottish investigator, Stuart Henderson, set up a chart containing the names of every passenger aboard the plane. Beside each name was the seat number, the location where each individual was found after the crash, who found them, how they were identified and their country of origin. Another chart provided an inventory for the pieces of debris that were being discovered.

In the months after the explosion, searchers collected thousands and thousands of fragments of the airliner and its contents from the vast countryside. Countless shreds of clothing and shards of metal were combed from the path of destruction by hundreds of men and women, who crawled on their hands and knees across the cold, wet ground and through the forests and alongside lakes and rivers.

Among these vital clues was a tiny piece of circuit board, discovered embedded in a small section of a cargo container from the aircraft. FBI and Scotland Yard forensic experts were able to determine that the circuit board came from a specific model of Toshiba radio. Additional fragments told the story of the bomb: 10 to 14 ounces of plastic explosive had been hidden inside the radio-cassette player.

At the same time, other experts were reconstructing the entire aircraft in a hangar at a secret location in Britain. As the pieces of the once-sleek, blue-and-white 747 were reassembled, they showed that the blast had come from the aircraft’s front cargo hold. Within that hold was a large cargo container, AVE 4041.

Blast characteristics on its pieces identified AVE 4041 as the location of the bomb.

Reviewing baggage records, investigators determined that the luggage in that container had been loaded aboard in Frankfurt, Germany, on the first leg of the flight. Among the bags identified was a large, brown, hard-sided Samsonite suitcase. When pieces of that suitcase were analyzed, the results proved that the suitcase had contained the bomb-laden Toshiba radio.

Further analysis from the reconstructed pieces of the airplane’s contents identified specific pieces of clothing inside the suitcase. Fabric fibers from the clothing were analyzed and traced to a particular manufacturer, who had sent the clothing to the island of Malta.

On the Mediterranean island, which lies between Libya and Italy, investigators discovered that clothing matching that found in the wreckage had been purchased on Dec. 7, 1988, at Mary’s House, a clothing store.

The man who bought the clothes was Abdel Basset Ali Megrahi, a Libyan-born officer in the Jamahiriya Security Organization, part of Libya’s intelligence service, according to the U.S. indictment. His name was first obtained from the mysterious diary, and records showed that Megrahi had stayed at the Holiday Inn about 300 yards from the clothing store.

Simultaneously, analysts at CIA headquarters in Langley, Va., were examining another clue discovered in the wreckage: a section of a green electronic circuit board about a quarter-inch square and wafer-thin. The circuit board, which was believed to have come from the timer used in the bomb itself, was found stuck in a piece of the clothing from the Samsonite suitcase.

A young CIA analyst, described by associates as “brilliant,” came up with the idea of trying to match the circuit board to bombs used in other terrorist acts. Through painstaking analysis, he discovered that a similar piece of electronics had been recovered from a 1986 attempt to blow up the U.S. Embassy in the African country of Togo.

He also found that, two years later, two men had been arrested in Senegal in possession of 20 pounds of plastic explosives and a triggering device. Although the men had been released and the device destroyed, a photograph taken by Senegalese authorities showed an identical circuit board. The plastic explosive seized in Senegal also matched the “fingerprints”--as forensic experts call the telltale characteristics of sophisticated explosive devices--of the Lockerbie bomb.

The Togo and Senegal incidents had another common factor: In both cases, authorities had linked the bomb and the explosives to Libyan intelligence agents. FBI and Scottish forensic experts set to work trying to discover who had made the timers.

“Having found a known timer, they then determined the manufacturer of that particular timer by looking at the circuit board and, utilizing their processes, uncovering the manufacturer’s initials, which had been attempted to be scratched out,” said Assistant Atty. Gen. Robert S. Mueller III.

The manufacturer was identified as a Swiss firm called Meister et Bollier. Acting Atty. Gen. William P. Barr said the Swiss company had manufactured 20 of the timers, known as Model MST-13, to specifications provided by Libyan intelligence. The devices were sold in 1985 to Izzel Din Hinshiri, Libya’s former minister of justice and current minister of transportation, according to Barr.

In the first months of the inquiry, investigators believed that the bomb had been detonated by a barometric timer, a type set to go off at a specific altitude. But the MST-13 was a digital device, set to detonate the bomb at a specific time.

In setting the time, the terrorists made a critical miscalculation. Had the bomb exploded a few minutes later, the jetliner would have been over water, and the thousands of pieces of debris would have been lost in the sea. The chance of piecing together that puzzle would have been virtually zero. The fact that the bomb went off over land was a stroke of good luck for the investigators.

One of the early mysteries was how the Samsonite suitcase got aboard Flight 103. Security procedures required that every bag be matched to a passenger, but investigators discovered that the suitcase was aboard as unaccompanied luggage.

In examining the baggage manifest for container AVE 4041, investigators found that the Samsonite suitcase had been among pieces of luggage transferred to the Pan Am flight in Frankfurt from Air Malta Flight KM 180. The flight had arrived in the German city from Malta’s Luqa airport at 12:41 p.m. on Dec. 21. The luggage was marked with the appropriate tags for transfer to the London-bound flight.

Because it bore the correct tags, German authorities missed the fact that there was no corresponding passenger on the plane.

The next steps were finding out how the luggage got those tags and how it got aboard the Air Malta flight. And the solution to that part of the puzzle remains something of a mystery. The indictment, returned by a grand jury in Washington on Wednesday and announced Thursday, provides only hints, and Justice Department officials declined to elaborate.

Somehow, investigators obtained a desktop diary belonging to Fhimah, the Libyan intelligence official, who had worked at Luqa airport for Libyan Arab Airlines. He had access to the baggage tags of every airline using the airport.

According to a diary entry on Dec. 15, 1988, Fhimah took baggage tags for Air Malta flights and kept them for Megrahi, who had left Malta after buying the clothes at Mary’s House. On Dec. 17, according to the diary, Megrahi returned on a flight from Zurich and went on to Tripoli, the capital of Libya. Fhimah flew to Tripoli on Dec. 18, and the two agents returned to Malta two days later. With them, says the indictment, was a large brown Samsonite suitcase.

The indictment says that Megrahi had bought clothes at Mary’s House to make the suitcase look legitimate if it were examined. Also inside the suitcase, according to the charges, was a Toshiba radio packed with explosives that Fhimah had stored at his Libyan airline office since the summer of 1988.

With its stolen baggage tags routing it to Pan Am Flight 103 in Frankfurt, the suitcase was placed “in the stream of international airline passenger luggage” being loaded aboard outgoing flights, according to the indictment. This required assistance from others at the Libyan airline offices in Malta, says the indictment.

The bag left Malta aboard Flight KM 180 and was transferred to container AVE 4041 aboard Pan Am Flight 103A, which went from Frankfurt to London later that same afternoon. At London’s Heathrow airport, the entire container was moved into the front cargo bay of the doomed Flight 103.

Thirty-eight minutes after lifting off from Heathrow, just minutes away from entering airspace above the Atlantic Ocean northwest of Scotland, the MST-13 timer detonated the plastic explosives inside the Toshiba radio tucked in the Samsonite suitcase in cargo container AVE 4041.

In the first months of the investigation, speculation about responsibility for the bombing had centered on Libya, Syria and Iran. But the evidence gleaned through the unrivaled international investigation traced the elements of the bomb decisively to Libyan intelligence officials, according to U.S. and Scottish authorities.

Along with trying to solve the bombing of Flight 103, authorities clearly are trying to convey a warning to terrorists that they will be detected no matter how sophisticated and elaborate their schemes.

“Today’s indictment is a landmark and sends a powerful message,” Barr told reporters.

But counterterrorism experts cautioned that the message of deterrence will be driven home only by solving another mystery--how to retaliate convincingly against the two suspects, who are believed to be back in their home country, and against the government that apparently sponsored them.

Times staff writer Robin Wright contributed to this story.

The Indicted Libyans

A look at the two Libyan Intelligence officials charged with the bombing of Pan Am Flight 103. Both are still at large. ABDEL BASSET ALI MEGRAHI Aliases: Abd Al Basset Al Megrahi Abdelbaset Ali Mohmed Al Megrahi Abdelbaset Ali Mohmed Mr. Baset Ahmed Khalifa Abdusamad Description: Date of Birth: April 1, 1952 Born: Tripoli, Libya Height: Approximately 5’8” Weight: Approximately 190 lbs. Marital Status: Married Occupation: Formerly chief of Airline Security Section LAMEN KHALIFA FHIMAH Aliases: Al Amin Khalifa Fhimah Mr. Lamin Description: Date of Birth: 1956 Born: Suk Giuma, Libya Height: Approximately 5’7” Weight: Approximately 190 lbs. Marital Status: Married Occupation: Station manager, Libyan Arab Airlines

The Lockerbie Disaster

A bomb explosion on the night of Dec. 21, 1988 killed all 259 people aboard the Pan Am 747 and 11 on the ground. 1. Blast ripped baggage hold. Explosive gas, channeled through the fuselage, blistered plane’s skin. 2. Fuselage ruptured, plane disintegrated. The skin cracked at the explosion site, The skin began to peel back. The plane broke apart within 3 seconds.

Intended Path of Flight 103 1. Flight originates in Frankfurt. 2. Plane takes off from London. 3. Plane crashes in Lockerbie, Soctland. 4. Flight destined for New York.

Source: Air Accidents Investigation Branch