Of the thousands of leads FBI agents chased in their 12-week manhunt for Andrew P. Cunanan, one of the best came in the form of a computer message just 10 digits long.

On a Thursday morning in early May, a telephone company in Pennsylvania registered a transmission from the cellular phone in a green 1994 Lexus belonging to a Chicago businessman, Lee Miglin, who had been found murdered four days earlier. The word went out that Cunanan, already suspected of slaying Miglin and two others, had been spotted, electronically at least.

Four hours later, the same phone number lit up again in Philadelphia, prompting state, local and federal law enforcement officers to mount an all-out search for Cunanan there. Even as detective teams fanned out, Philadelphia police announced the presumed break in the investigation to the news media.

Cunanan apparently heard the news that day, and police and FBI investigators believe he decided to ditch the Lexus and find another vehicle. The day after the police announcement, Cunanan allegedly drove to a remote cemetery in New Jersey and killed caretaker William Reese. Investigators said Cunanan then took Reese's pickup and left the Lexus behind.

Police use of publicity in investigations of dangerous fugitives is designed to increase public awareness of a fugitive in the hope that an alert citizen will notify investigators in a timely fashion and allow them to make an arrest.

"We tried to put out as much information as possible to the public and the media so they could help us locate Mr. Cunanan," said William J. Esposito, deputy director of the FBI, at a news conference yesterday. "If only one out of a thousand calls from alarmed citizens actually paid off," Esposito said, "it is worth it."

But in the nationwide manhunt for Andrew Cunanan, local police coordination with the FBI varied widely -- and Cunanan remained at liberty as a result. In the critical area of South Florida, miscues by local law enforcement agencies deprived police and the FBI of several opportunities to arrest Cunanan before he allegedly killed Italian fashion designer Gianni Versace, then took his own life, government officials said yesterday.

Indeed, law enforcement officials said that until a caretaker alerted police to an intruder Wednesday on a Miami Beach houseboat, the Philadelphia incident was the only time investigators believed they had a real chance of apprehending Cunanan.

Missed opportunities rankled some investigators. After the "America's Most Wanted" television show featured Cunanan repeatedly, for example, a cashier at a Miami Beach sandwich shop recognized the fugitive and called 911 on July 11. But the Miami Beach Police Department failed to pick up his trail.

After Cunanan used his passport and his real name to pawn a rare coin, Miami Beach police failed to check the pawnshop's report of the transaction. Other local law enforcement agencies, particularly those in New York and Minnesota, responded aggressively to the FBI alerts about Cunanan. But the fugitive was already in South Florida, and despite having taken few precautions against being identified by police, he roamed streets and stores until the July 15 murder of Versace.

After that, police announcements that Cunanan was the prime suspect forced him into hiding -- and it was only then that police got the "lucky break" the publicity strategy was designed to produce. A caretaker for a Miami Beach houseboat alerted police to an intruder and an apparent gunshot. Police and FBI agents swarmed to the scene, and Cunanan killed himself sometime afterward.

Cunanan first came to the attention of law enforcement authorities on April 29 when Minneapolis police were called to an apartment where a corpse had been discovered. In addition to the bludgeoned body of Jeffrey Trail, a 28-year-old businessman, the police found a nylon gym bag with Cunanan's name on it, according to court documents. Inside they found an empty handgun holster and a box of .40-caliber Golden Saber bullets. Ten bullets were missing.

Police immediately began a search for the owner of the apartment, architect David J. Madson. They also began looking for Cunanan, who they learned had been visiting there for at least four days. On May 3, two fisherman discovered Madson's body on the grassy shore of East Rush Lake, about 40 miles from Minneapolis. Madson had been shot three times with a 10mm semiautomatic, and his red Jeep Cherokee was missing.

So was Cunanan.

Within hours, police in Minneapolis and Rush Lake connected the two murders and decided that Cunanan was the prime suspect.

But by then Cunanan was long gone, investigators said. They believe he was in Chicago on the weekend of May 3-4, and that he encountered Miglin, the Chicago developer, then, probably in the garage of Miglin's swank Gold Coast town house. The body of the 72-year-old real estate investor was discovered May 4. Miglin had been tortured and mutilated, and his Lexus was gone.

Several days later, on May 7, police discovered Madson's Jeep near Miglin's home.

That day, the FBI became officially involved in the search for Cunanan.

The FBI was not responsible for investigating the murders of Trail, Madson and Miglin. But when Madson's Jeep turned up in Chicago, the FBI opened an investigation of Cunanan as a subject wanted for unlawful flight to avoid prosecution. Working with state and local police agencies, the FBI task force began enlisting the help of law enforcement officials around the country in chasing down leads and sightings involving Cunanan. The information received was fed to the FBI's Minneapolis field office where it was loaded into the bureau's Rapid Start computer program, which is designed to track and collate thousands of bits of seemingly unrelated information generated in big, fast-moving investigations.

At FBI headquarters in Washington, top officials began holding twice-a-day conference calls to monitor the progress of the investigation and as Esposito put it, to "make sure nothing fell through the cracks."

One of the first steps the FBI took was to begin working with police in San Diego, Cunanan's home town, on an all-out field investigation of the fugitive. Local and federal investigators searched Cunanan's apartment there and sought out his friends. "His roommate provided us with a box of Cunanan's belongings which contained address books and photographs and other personal things," said Lt. Jim Collins of the San Diego police homicide department. Police and FBI investigators have now determined that after he allegedly murdered Miglin, Cunanan departed for New York City. Authorities placed Cunanan in Manhattan between May 5 and May 8, based on dated receipts found in the red pickup truck belonging to Reese that he left behind after the Versace murder, law enforcement officials said. They included a receipt dated May 5 from the West Side Club in the Chelsea section of Manhattan, a men's sauna with gym and steam room where members can rent a room with a cot for four hours for $14. In addition, there were three movie theater stubs from a theater in Chelsea, one dated May 7 for "Liar, Liar," another dated May 8 for "The Devil's Own" and a third that was illegible, according to authorities. Another receipt, found later at the Normandy Plaza hotel where Cunanan stayed in Miami Beach, was for a cash purchase from the Original Levi's Store on West 57th Street in Manhattan. That was dated May 5.

On May 8, Cunanan evidently tried to use the cellular phone in Miglin's Lexus in Philadelphia. He did not complete a call (he would have had to have Miglin's identification code to do so). But the attempt to activate the phone registered on a phone company computer. The phone company notified investigators.

Law enforcement officials said they have several indications that Cunanan knew he had come dangerously close to giving himself away. Among the clues was the condition of the phone. "We think he knew about the cell phone because he tried to destroy it," an official said. "He tried to tear it out {of the car}, disconnect it, beat it up to the point it wouldn't work."

Investigators believe that on May 9, the day after he turned on the cell phone, Cunanan made a stop at the information center at the Delaware Memorial Bridge and was provided with a pamphlet offering information on Fort Mott State Park, which is located in Pennsville, N.J. The Finn's Point National Cemetery is located close by in a remote area about 14 miles from the nearest interstate turnoff.

State park employees told police and the FBI that they saw a man fitting Cunanan's description lying on the grass in the park on the afternoon of May 9, several hours before William Reese, the cemetery's caretaker, was murdered in his office. The remote, five-acre cemetery has almost no traffic because most of its graves hold bodies from the Civil War era -- Confederate prisoners and Union guards who died at nearby Fort Delaware after the Battle of Gettysburg -- and there is no more room for bodies. Cunanan may have been watching Reese because it appears that the caretaker had just finished work at the time he was murdered. Investigators said he was killed with a shot to the head from the same 10mm semiautomatic used to kill Madson.

The FBI wrongly assumed that Cunanan would head for the large anonymous crowds of New York City, but even though he was headed in the opposite direction -- toward Florida -- what happened in New York following Reese's murder is a textbook example of how a fugitive pursuit should be undertaken, law enforcement authorities said.

Within hours after Reese's murder, police throughout New York were on high alert for Cunanan. For the first days after Reese's body was found, warnings about Cunanan blared every two hours across the state police radios; after that, they were broadcast at the start of every shift. Officers were issued written copies of the alert when they reported for duty and were required to sign certifications that they had read it.

The New York City police and the New York office of the FBI also enlisted the help of the city's Gay and Lesbian Anti-Violence Group.

"They asked us to get his picture out as widely as we possibly could in the community," said Christine Quinn, executive director of the anti-violence project. "We created a flier with pictures of him and his description and began distributing them widely in neighborhoods with large gay and lesbian populations. We asked bar and club owners to make the fliers very visible and to make sure that staff people knew what he looked like and knew exactly what to do if they spotted him.

"Well over 60 bars were participating with us. As we got calls of potential or alleged sightings," Quinn said, "we forwarded them to the FBI and the New York police. We stayed in touch on daily basis."

Quinn's group also offered a $10,000 reward for information leading to Cunanan's capture and conviction -- the first such reward that was offered, although the FBI and New York Mayor Rudolph W. Giuliani later offered similar rewards.

"We saw some positive things, but it wasn't consistent on a national level," Quinn said. "That lack of consistency, for example, in Miami, can have a huge impact in the effectiveness of law enforcement."

Early on in the fugitive investigation of Cunanan, FBI officials in Minneapolis began pushing to have his name added to the bureau's Ten Most Wanted List, a device used since 1950 to generate publicity about fugitives. But they were thwarted because there was no room on the list. But on May 20, an opening occurred, and on June 12, after FBI headquarters reviewed the Cunanan file, he became the 449th person to make the list.

Placement on the list does not directly affect the resources or strategy the FBI applies to a search, officials said, but it does mean that an FBI office that receives a lead on a case must have agents in action within an hour -- regardless of when the lead comes in. During the course of the manhunt for Cunanan, about 1,000 FBI agents took part in the investigation, Esposito said yesterday. CAPTION: A CROSS-COUNTRY MANHUNT Law enforcement officials chased thousands of leads in their attempt to corner Andrew Cunanan. At each close call, he had already vanished. 1. SAN DIEGO On April 24, Andrew Cunanan had a going-away party at California Cuisine. He told friends he has business to take care of in Minnesota. 2. MINNEAPOLIS On April 25, Cunanan flew to Minneapolis and met with David Madson, 33, an ex-boyfriend. That weekend, the two called Jeffrey Trail, 28; Trail went to Madson's apartment Sunday, the day he was killed with a claw hammer. On April 29 in Madson's apartment, police found Trail's body rolled in a rug, along with some .40-caliber bullets. 3. RUSH CITY, MINN. On April 29, Cunanan and Madson went to Rush City. On May 3, two fishermen found Madson's body on the edge of East Rush Lake. He had been shot, probably on May 2, with .40-caliber ammunition; that day two men fitting the description of Madson and Cunanan were seen in Madson's Jeep. 4. CHICAGO On May 4, the body of Lee Miglin, 72, was found in the garage of his town house. He had been bound with tape, his throat slashed with a saw and his chest jabbed with pruning shears. Madson's Jeep was found nearby, and Miglin's Lexus was missing. 5. NEW YORK Receipts from a men's sauna and Levi's store and movie ticket stubs place Cunanan in New York from May 5 to May 8. 6. PHILADELPHIA On May 8, police tracked two cellular calls to the phone missing from Miglin's Lexus. 7. PENNSVILLE, N.J. On May 9, William Reese was found shot to death in an office at the cemetery he tended. Miglin's Lexus was found; Reese's pickup truck was missing. 8. FLORENCE, S.C. On May 10, a license plate was stolen from a K Mart parking lot off I-95. 9. MIAMI BEACH Detailed at right. IN MIAMI BEACH 1. About May 12 -- July 14: Cunanan stayed at the Normandy Plaza hotel. He registered under an alias and used a French passport. 2. July 7: At Cash on the Beach, Cunanan, using his real name, pawned a 18-carat gold coin stolen from Miglin. 3. July 11: An employee of Miami Subs called 911, saying Cunanan had been in the shop. 4. July 15: Gianni Versace, 50, was shot to death outside his Ocean Drive mansion. 5. July 15: Reese's pickup was found in a nearby parking garage, where it had been since June 10, according to the parking receipt. Cunanan's passport and some of Miglin's belongings were inside; the truck bore the missing South Carolina plate. 6. July 23: Cunanan shot himself in the head on the second floor of a houseboat that belongs to Torsten Reineck. He used the same gun that killed Versace. CAPTION: Madson CAPTION: Trail CAPTION: Cunanan CAPTION: Miglin CAPTION: Reese CAPTION: Versace CAPTION: Houseboat where Cunanan shot himself