(AP) – In the early morning of July 1, 1973, Col. Yosef Alon – a charismatic former fighter pilot who helped establish the Israeli Air Force – was gunned down in his suburban Maryland driveway.

Thirty-four years later, the case is unsolved.

Many suspected that the 43-year-old diplomat was the target of Arab terrorists, but no evidence to support that theory surfaced. The FBI case was officially closed in 1976.

There were no arrests. No murder weapon. Nothing. As far as the public knew, Alon’s killing was a mystery with no real leads – the perfect crime.

But that was not the case, according to six-month investigation by The Associated Press.

Recently declassified CIA documents, Alon’s voluminous FBI case file and interviews reveal that years after the shooting, the agency received a tantalizing tip about who likely pulled off the assassination and how the deadly plot was carried out.

Now, partly as a result of the AP’s findings, former FBI agents who have never spoken publicly about the long-dormant murder believe the case should be reopened.

With the passing of decades and the FBI’s ability to operate abroad, the dynamics of this case might have finally tilted in the favor of law enforcement. These agents say people might be willing to talk and provide answers about who killed Yosef Alon.

“In all probability this could be solved,” said Fred Burton, who briefly investigated the case in the late 1980s when he was a U.S. State Department counterterrorism agent.

“It’s time to take another look at this,” said Stanley Orenstein, 70, who helped run the FBI’s initial criminal probe into Alon’s death and retired in 1986. “It was important enough at the time, and it’s important enough now.”

___

Alon’s mission in America was vital. Beginning in 1970, he was assigned for three years to the Israeli Embassy in Washington as the assistant air and naval attache.

He was not a spy. He was a rugged flyboy who had completed 75 missions dating back to the War of Independence in 1948, a man who helped foster a generation of pilots and led the country’s first jet squadron of French-built Mirages.

His posting made perfect sense. He knew planes. He knew what his country needed to maintain its military edge over its enemies. He worked vigorously to procure sophisticated American F-4 Phantoms and other weaponry for the Israeli Air Force as his country battled Egypt.

“Alon was by far the most persistent and aggressive individual who represented a foreign government,” a retired U.S. Air Force officer told the FBI.

Egypt, though, was not the only threat facing Israel.

In 1972 a Palestinian terrorist group named Black September – a violent offshoot of Yasser Arafat’s Fatah organization – killed 11 Israeli athletes at the Olympic games in Munich.

Israel decided to avenge the deaths, and the two sides were locked in a deadly tit for tat that eventually reached America, a startling escalation in the conflict.

Black September tried to detonate three car bombs in New York City in March 1973, timed to coincide with Israeli Prime Minister Golda Meir’s visit. The powerful bombs, which might have killed or wounded hundreds, failed to explode.

It was a tense and dangerous time, but Alon betrayed no fear. Though his job was critical to Israel’s national security, he didn’t feel that he would be singled out for attack.

He also was fatalistic: If Black September wanted him dead, they’d get him.

___

Newspaper reports on Alon’s murder provide a rough sketch of what happened the night he was killed – but the more than 7,000-page FBI file, obtained by the AP through the Freedom of Information Act after a three-year wait, provides the first authoritative version of what happened and previously unknown details about the investigation that followed.

Alon and his wife, Dvora, spent about 2 1/2 hours mingling with friends and diplomats at a dinner party in honor of an embassy staffer who was returning to Israel. Alon drank heavily but managed to drive to their Chevy Chase home safely around 12:30 a.m.

Alon parked the green Ford Galaxie about 1 a.m. His wife got out first. The diplomat hesitated, grabbing his maroon sports jacket from the back seat.

When Dvora reached the porch, about 20 to 30 feet away, she heard gunshots. She unlocked the door and ran inside the brick home, quickly turning on the exterior garage light – and then quickly turning it off again, realizing the shooter could see her as she looked out the window.

She saw a light-colored car with its headlights on, driving slowly away. She called 911, the embassy and the Montgomery County Police Department. Rushing outside, she discovered her badly wounded husband on the front lawn.

She and her eldest daughter, Dalia, 18, tried to stanch the bleeding with bathroom towels as they awaited the rescue squad. Yosef Alon was taken to the hospital, where he died at 1:27 a.m.

An autopsy revealed Alon had been hit five times. Four bullets caused superficial damage, and a fatal one struck his heart.

The same day, monitors from the State Department heard this Palestine Liberation Organization radio broadcast from Cairo:

“After the assassination of martyr Mohammed Boudia at the hands of the Zionist intelligence elements in Paris, Colonel Yosef Alon … was executed,” the Voice of Palestine radio announced. “His is the first execution operation carried out against a Zionist official in the U.S.”

Boudia was a high-ranking Black September operative living in Europe. He died in an explosion in Paris, two days before Alon; it is widely believed that Mossad agents planted a bomb under the driver’s seat of his parked car.

___

The FBI made the case a priority. Apparently, said the Washington Post in an editorial, it was the “capital’s first political murder of a foreign diplomat.”

The FBI launched a massive investigation dubbed “MURDA,” or the “Murder of Assistant Air Attache Col. Joseph Alon,” according to the partially redacted FBI file.

Evidence was scarce. Investigators discovered a “perfectly shaped bullet,” fired from a foreign-made, .38-caliber revolver. The bullet was pulled from the ground next to Alon’s car. The FBI narrowed the possibilities to a Titan Tiger or Arminius, of which a staggering 74,000 were in circulation.

But unless authorities could match a gun to the copper-jacketed, military bullet dubbed “Q6,” the evidence was useless.

FBI agent Frank Corn surmised the killer hid behind a large bush next to the garage, shot Alon and fled to a nearby getaway car with a waiting driver – perhaps the car Dvora spotted.

The gunman was only about six feet away when he opened fire.

Mr. Corn, like other agents, felt that whoever had killed Alon was a professional and had stalked him.

“That was the feeling that I got,” said Mr. Corn, now retired. “That they knew his movements.”

After dismissing robbery and romantic-entanglement scenarios, FBI agents focused on the most logical one: an act of Arab terrorism.

“The thrust of this investigation is now directed at Arab travelers who might be connected with the case,” according to an FBI memo written in July 1973.

The FBI also began working off a list of approximately 90 people classified as “Arab terrorists” or members of “Arab extremist organizations.”

The FBI checked hotel registration cards, airplane manifests and records of rental cars for Arabic-sounding names, but with no success. They also looked into Arab students and faculty at Washington-area colleges and universities. Again, no luck.

Israel’s domestic intelligence agency, Shin Bet, supplied leads: at least one man from Munich, a hot bed of activity involving the Popular Front for the Liberation of Palestine; a Black September activist who had visited the United States on an information-gathering mission; an Arab living in Canada; a top Kuwaiti Embassy official and his wife. The PFLP also took responsibility in a 1974 interview with a Kuwaiti newspaper, but the FBI apparently dismissed that uncorroborated claim.

The information was merely another layer in a complex case that had plenty of intrigue.

“We knew there was a lot of a backroom stuff going on that we didn’t know about,” said Stanley Orenstein, the FBI man who ran the investigation at the start.

Within a year of Alon’s murder, Mr. Orenstein visited FBI agent Jim Kennedy, since deceased, at the Baltimore bureau.

Mr. Kennedy suggested Mr. Orenstein to ease up on his investigation. “It’s been taken care of,” he said, according to Mr. Orenstein. Mr. Kennedy had received information from the FBI in Washington that the Israelis had dealt with Alon’s killers.

How did he know this? Mr. Kennedy didn’t say.

Mr. Orenstein said he walked away with the clear impression the Israelis had “settled the score by retaliating in some way without necessarily hitting the shooter and the helper.”

The puzzling investigation was still getting “preferential treatment” in 1974, according to FBI documents. But in 1975, the case started to wind down. The next year, it had run its course.

“No suspects have been developed,” according to an FBI memorandum dated March 1976. “Numerous allegations as to the possible individual or group perpetrating this crime have been investigated with negative results. All logical leads have been covered. Baltimore recommends this case be closed, subject to reopening if new information is received.”

“It just became what we call in the business – a dead cigar,” Mr. Orenstein said. “You’re never gonna smoke it again and it goes sour.”

___

Then, a potential break.

In February 1977, FBI Director Clarence Kelly fired off an internal memo based on a promising CIA tip – one that reignited this “dead cigar” and fit the modus operandi of the terrorists perfectly.

According to portions of the FBI file that remain secret, “A sensitive source advised that the Black September Organization was responsible for the crime.”

The CIA had learned from a “Fedayeen senior official” that two students had entered America via Canada and traveled on either Lebanese or Cypriot passports to Washington.

They stayed with other students and made contact with a local professor who helped them carry out the mission. The professor rented a car for the students and placed the weapons inside it. After the students had shot Alon, they ditched the rental car with the weapons still inside.

The students got into another car they had rented and drove to Dulles International Airport, then took a domestic flight to the West Coast and ultimately ended up in the Middle East via the Far East, the source told the CIA.

That set off a flurry of FBI activity.

The FBI director told agents to scour passenger manifests for all names – not just Arabic-sounding ones as had been done initially – for certain flights leaving the morning Alon died.

“Investigation should include all, repeat all, passengers,” according to the February 1977 memo. “This case should receive aggressive and prompt investigation.”

Agents checked flights from area airports to the West Coast that left after 11 p.m. June 30 and before 7 a.m. the next day. There were no such flights. Manifests from international flights leaving about the same time and other records had been destroyed.

Too much time had passed.

Efforts to determine the identity of the mysterious professor also failed. The investigation was closed later that year, and in 1978 the FBI’s Baltimore office had destroyed all “evidentiary items,” including the bullet known as “Q6.”

“That’s not only regrettable – it’s worse than that,” Mr. Orenstein said. “That should never happen in a homicide. Why would the FBI do that? It’s just plain wrong.”

The CIA apparently never learned anything more about the case. In August 1978, secret briefings were held at CIA headquarters in Langley, Va., according to memos that were declassified recently.

The briefings – one of which touched upon Alon – were given to two congressional staffers investigating the activities of foreign intelligence services in the United States. Using only their first names, CIA officers discussed what the agency had learned about Alon.

“It was noted that information that came to our attention years after the assassination indicated that Fatah/Black September was ‘probably’ responsible for the murder, and that a two-man hit team had entered the U.S. specifically to carry it out and had left immediately afterward. The FBI has been unable to confirm any of the information obtained by …”

The rest of the passage was blacked out to protect government sources and methods, according to the CIA.

Former intelligence and government officials think the memo, an internal CIA document, was based on solid information – the same that was given to the FBI in February 1977.

Duane Clarridge served as the CIA’s deputy chief of the Near East Division for Arab operations from 1974 to early 1978. He spent 33 years with the agency.

“They would have considered it reliable,” Mr. Clarridge said. “I don’t think they would have walked out there with that if they didn’t have some confidence.”

Mohammed Oudeh of Black September masterminded the Munich massacre and now lives in Damascus. Oudeh, who was imprisoned in Jordan in 1973, told the AP he didn’t know anything about the Alon operation. As far as he knows, Black September never carried out operations in Washington, or the States.

But the CIA’s tip – if true – leaves several lingering questions. What happened to the rental cars and the weapons? Was this lead given to the Israelis? Why wasn’t the source debriefed by FBI agents? Who was this “Fedayeen senior official” who tipped off the CIA about the two students and the professor?

Is he still alive? Can he provide more information? What about the professor? Does he still live in America?

Can this cold case finally be closed after more than three decades?