On May 13, 1981, shortly after 5:00 p.m., Pope John Paul II, the first non-Italian pope in 455 years, the first Slavic pope ever, and — to the great dismay of the Soviet Union — an intensely anti-communist Pole from the heart of the Communist Bloc, slowly rode through St. Peter’s Square in his white Fiat “Popemobile.”

Among the onlookers gathered for the pontiff’s weekly audience were Americans and Italians, Chinese and Germans, Latin Americans and Africans — Turks and Bulgarians. And observing intently from still further away were Russians posted at the Kremlin. Moscow had recently described this pope as a “malicious, lowly, perfidious, and backward… toady of the American militarists,” who was seeking to undermine communism with his “overseas accomplices” and “new boss in the White House.” His new boss: Ronald Reagan.

That was their cynical fear, their worst fear, and very legitimate fear. The Soviets loathed the prospect of this stridently anti-communist pope working with the stridently anti-communist president against their objectives.

Make no mistake: Pope John Paul II and President Ronald Reagan scared the Kremlin. And with good reason. The pope implored his people to choose God’s side over what the Protestant Reagan and the Roman Catholic Church both called “godless communism” and against what Reagan labeled an “Evil Empire.”

Soviet officials knew this Polish pontiff was a grave affront to their mortal existence. If only he was dead. Frankly, they wanted him dead. And now, on May 13, 1981, they were ready to take their shot.

The man tasked to do the job was a 23-year-old Muslim Turk named Mehmet Ali Agca. Later, he would name seven accomplices, all working under a plan conceived by the Bulgarian secret service, one of the communist world’s most restrictive intelligence services and the one most subject to Moscow’s control. It was joked that Bulgaria was practically the 16th Soviet republic. The Bulgarians were dutiful stooges of the Kremlin. They didn’t do anything without Soviet approval.

Agca stood poised in position. He held a 9-millimeter Browning semiautomatic, as John Paul II edged closer. He lifted his pistol. Four shots were fired, two of which hit the pope. The physically fit pope folded and collapsed, his white figure sinking into the arms of his aides.

The pain was intense. He was rushed to the hospital, where he would require six pints of blood and five-and-a-half hours of surgery.

Just before he passed out, he whispered to a nurse, “How could they do it?”

Who he meant by “they” was not specified. But this Polish pontiff, Public Enemy No. 1 to the communist empire, apparently had a hunch.

So did his new friends in the Reagan White House.

Who Ordered the Hit?

At the time and ever since, many suspected that Moscow was behind the assassination attempt. A few years after the shooting, Agca himself fingered the Bulgarians as his accomplices, though Sofia and Moscow vigorously denied any involvement. Early on, Italian investigators began gathering critical information, more of which would emerge from files after the Soviet collapse — smuggled out of Moscow by a KGB archivist in 1992.

Yet, there are several tantalizing threads to this story that have not been reported and which I’ve been exploring since I started filing FOIA requests in 2000 and began interviewing numerous Reagan officials and confidantes. I lay out that evidence in many pages in my new book on John Paul II and Ronald Reagan, A Pope and a President. I cannot here give due justice to the weight of the material, but I can summarize it.

First, I can affirm what many figured: The Soviets ordered the attempted assassination of Pope John Paul II. The plot is traceable to Moscow — but not, it turns out, to the KGB, or at least not entirely. It was the Soviet GRU, military intelligence, that ordered the hit on the world’s leading religious figure, though the GRU proceeded with the go-ahead of the odious head of the KGB, Yuri Andropov, who had been Vladimir Putin’s boss.

For the record, I cannot imagine that Putin had a scintilla of involvement in this conspiracy. He wasn’t high-level enough; only the rarest Soviet officials had any knowledge of this — of what William Safire would dub “The Crime of the Century.” That said, to this day, Putin has been a major protector of the GRU and the KGB since he came to power. I’ll return to that point in a moment.

And that relates to a second crucial finding in my research: Ronald Reagan’s CIA director, Bill Casey, ordered a super-sensitive investigation of the case. Casey, like Reagan, like top Reagan officials such as Bill Clark and Cap Weinberger, suspected Moscow from the outset. That investigation, conducted by a tight-knit group under Casey’s command, identified the GRU as the culprit. That report and its implications were so explosive that the full details have never been released or even acknowledged. Only a privileged few ever saw it; one source with knowledge of the report told me, “I’ve never, ever, in all my years, seen anything as secretive as that document.” My source called it “the most explosive report of the twentieth century.”

Which leads to a third intriguing finding in my research: Ronald Reagan learned, too. He was informed directly by Casey. President Reagan was one of those few who learned that Moscow had ordered the shooting. I believe that Casey briefed Reagan on that explosive finding on May 16, 1985, at 11:02 a.m. in the White House.

Fourth, I’m certain that Casey briefed John Paul II on the investigation, which merely confirmed what the pontiff had suspected and was telling close aides as early as mid-1981. The pope did not want Casey or Reagan to publicly disclose their conclusions or suspicions, because of fear of the potential international damage, because he knew Moscow would furiously deny the charges and launch a vicious disinformation campaign, and because, in effect, what was done was done.

And besides, what was important was what John Paul II hoped he and Ronald Reagan could do together in the positive: They could join forces to defeat this Soviet menace and peacefully end the Cold War.

To that end, there was another assassination attempt of similar importance: Reagan had been shot on March 30, 1981. He likewise nearly bled to death.

The Soviets had worried about an anti-communist, anti-Moscow kinship between the pope and the president. Now, they had to worry more so. The pope’s and the president’s unique near-death experiences brought them closer.

That bond became apparent when Reagan and John Paul II met for the first time in June 1982 at the Vatican, where they confided their mutual conviction that God had spared their lives for the higher purpose of defeating Soviet communism.

And the rest, as they say, is history. These two men would work together to rewrite the story of the end of the 20^th century, despite the worst efforts of Moscow.

Trump, Putin, and Pope Francis?

And yet, the full history of this rather enormous and rather dramatic story has never been released. And maybe that’s where our new president, today, could step in.

How might this involve Donald Trump? Here’s how: He’s one man who could help get to the bottom of this.

In the mere days since my book was officially released on May 1, I’ve been told already by one source that another president (after Reagan) knew about the Casey investigation, but the pontiff likewise requested that this second president not raise a fuss and that he keep any documentation quiet for the time being. But today, in 2017, there should be no such constraints — quite the contrary. And that’s where our new president surely could help. In fact, there are three ways:

First, President Trump could press the Langley-Washington bureaucracy to fully release all that Casey’s team learned about the Russians’ role in trying to murder a pope. I’d really like to see Trump or someone in his administration seek the declassification of whatever materials our federal government is still holding.

Second, President Trump could ask Putin and the Russians for some action. Again, Putin was in the KGB throughout the 1980s. I’m sure he had no knowledge of what happened at the time, in May 1981, but he surely now, in May 2017, has knowledge. Putin has been the No. 1 man in Russia — the strong man, the authoritarian — since 2000. Surely he knows. Would Donald Trump be willing to prod Putin and the Kremlin?

Donald Trump is, of course, extremely bold and candid. He never hesitates to say what’s on his mind — via his voice, his Twitter account — and he doesn’t mind being politically incorrect or politically daring. He insists he will be no lap-dog to Putin and will stand up to the Russians.

That being the case, he should directly ask the Russians about their role in the unresolved crime of the century. The Russians have never conceded their involvement. It’s time for an answer.

And third, Trump could even appeal to the Vatican and Pope Francis. We learned just yesterday that he will be visiting the Vatican this month in his first foreign trip. A president’s first trip abroad is a big deal, and Trump has decided the Vatican will be part of it.

And in all of this, Donald Trump should think about a key group pivotal to his electoral triumph: It was Roman Catholics who arguably elected Trump last November. They voted for him 52-45 percent, whereas the nation as a whole voted against him 48-46 percent. Catholics normally mirror the popular vote but not this time. Catholics made up nearly one in four voters; they gave Trump millions of votes. Trump’s Catholic supporters would be thrilled to see him get to the bottom of the attempt to assassinate their beloved and literally saintly Pope John Paul II. And if there’s one thing we know about Donald Trump, he likes to take care of his friends.

Well, he has many friends who’d love to get some resolution — once and for all — of this crime of the century that exploded on May 13, 1981.

Paul Kengor is professor of political science at Grove City College in Grove City, Pennsylvania. His latest book is A Pope and a President: John Paul II, Ronald Reagan, and the Extraordinary Untold Story of the 20^th Century.