Sixty-five years ago this month, Gen. George S. Patton Jr., hero of World War II and an outspoken critic of the Soviets, was en route to a Sunday hunting trip, a day before permanently leaving Europe, when he was critically injured in a vehicle accident on a deserted two lane highway near Mannheim, Germany.

A large US army truck that Patton’s driver later said was waiting for them, suddenly — and without signaling — abruptly turned into his limousine’s path, causing a head-on crash. Even though Patton had an aide with him and the driver of the truck had one or two passengers in the cab, no one but Patton was hurt. He suffered a paralyzing broken neck.

Despite it being early on a no-work day, a horde of military personnel, including a brigadier general, quickly arrived at the scene. And although there were facilities in Mannheim, he was taken to a hospital 20 miles away where, when he arrived, the prognosis was bad. They expected him to die.

But the tough general, vowing to go home and tell “block-busting secrets,” rallied. And in a little over a week he was fit enough to be readied for a grueling trans-Atlantic flight home. On the eve of that flight, he had a sudden relapse. Blood embolisms choked his breathing. Within 24 hours he was dead.

Though he was a top general in Europe, had mysteriously requested a guard be posted outside his room, and rumors that he’d been murdered were rife, there was no autopsy. Bafflingly, the driver of the truck and his passenger or passengers disappeared, never to be heard from again.

Today, all reports and subsequent investigations of the crash — and there were at least five — have vanished.

It is a mystery for which even archivists have no explanation.

Was Patton, who foresaw the Cold War, wanted to fight the Russians to stop it, and was threatening to tell damaging secrets about how badly the war was run, assassinated?

The cause of death was ruled accidental, but two witnesses have emerged to dispute the official story. The first is Douglas Bazata, an Office of Strategic Services agent in World War II, the forerunners of the CIA. He claimed that he, an OSS assassin, was asked to kill Patton by OSS chief Gen. William “Wild Bill” Donovan. The order was the culmination of a long-running plot that had started as a non-lethal “stop Patton” plan.

Later, in interviews with me before his death in 1999, Bazata enlarged that scenario, claming that he, along with a Russian accomplice, set up the Dec. 9 “accident,” and that others — he believed Soviets — had finished the job in the hospital.

Though it is not well known, the OSS had an alliance with the NKVD, the Soviet spy network, during and after the war.

The other witness was Stephen J. Skubik, a Counter Intelligence Corps agent attached to Patton’s armies. After the war he continued working as a CIC agent amongst Soviet-dominated Ukrainians whom, he said, warned that Stalin had put Patton on a NKVD hit list. When he reported the plot to Donovan, the OSS chief jailed him. Following Patton’s death, he had to flee Germany in fear for his life.

During the war, Patton had angered the Roosevelt administration with his anti-Russian antagonism. FDR, believing the Soviets crucial to maintaining world peace, wanted them appeased and had acquiesced to their domination of Eastern Europe. “We’ve kicked the hell out of one bastard,” Patton lamented, only to “help establish a second one . . . more evil and more dedicated than the first.”

By late 1945, with the like-minded Truman continuing FDR’s pro-Kremlin policies, Patton was the loudest voice against the Democratic administration. No longer needed for war, he’d been exiled to an almost meaningless command. He was angry. And on the eve of the accident, was vowing to tell, among other secrets, how badly Gen. Dwight Eisenhower had conducted the war, how it could have ended much sooner — thus saving many Armerican lives — and to rally Americans against the Soviets.

The crash outside Mannheim alone begs many questions. What was the truck doing waiting for the Patton car? Why did it suddenly turn without signaling? The driver, Robert L. Thompson, was not authorized to have the vehicle, and having passengers was in violation of rules. Thompson not only was not charged, he vanished. Years later, I tracked him. He had died, but even his family said it didn’t surprise them if he’d been involved. He’d been an opportunistic black marketer in postwar Germany where, in unknown dealings, he’d made a “suitcase of money.”

What if Patton had lived? In 1945, he was one of the most popular figures in America. If he had wanted, he could have run for office. If he’d gotten his way — fight Russia when they were weak — who knows if the Cold War would have happened? He certainly would have besmirched Eisenhower’s reputation, which might have kept him from the Presidency.

It is clear Patton’s death has been covered up. I think there is sufficient reason to initiate an official investigation. Until the truth is revealed, the rumors will persist, crucial history may be lost and an enormous crime may go unpunished. Patton deserves better.

Robert K. Wilcox is the author of “Target: Patton — The Plot to Assassinate General George S. Patton” (Regnery), out now.