Who shot Osama?

He’s out there somewhere, an instant icon in the annals of American conflict, the ultimate big-game hunter. But an enigma, too, his identity cloaked for now, and maybe forever.

He is the unknown shooter. The nameless, faceless triggerman who put a bullet in the head of the world’s most notorious terrorist.

Yet there are clues, and the beginnings of a portrait can be pieced together from scraps gleaned from U.S. officials. A trio of former Navy SEALs — Eric Greitens, Richard Marcinko and Stew Smith — helped us fill in the blanks, drawing from their experiences to develop a kind of composite sketch of an elusive historic figure in real time.

He’s likely between the ages of 26 and 33, says Marcinko, founder of the elite “SEALs Team 6” — now known as DEVGRU — that many believe led the assault on bin Laden’s compound in Abbottabad, Pakistan. He’ll be old enough to have had time to hurdle the extra training tests required to join the elite counter-terrorism unit, yet young enough to withstand the body-punishing rigors of the job. The shooter’s a man, it’s safe to say, because there are no women in the SEALs. And there’s a good chance he’s white, though the SEALs have stepped up efforts to increase the number of minorities in their ranks, Marcinko and Smith say. A “positive thinker” who “gets in trouble when he’s not challenged,” Marcinko suspects, a man who “flunked vacation and flunked relaxing.”

He was probably a high school or college athlete, Smith says, a physical specimen who combines strength, speed and agility. “They call themselves ‘tactical athletes,’ ” says Smith, who works with many prospective SEALs in his Heroes of Tomorrow training program in Severna Park. “It’s getting very scientific.”

Marcinko puts it in more conventional terms: “He’ll be ripped,” says the author of the best-selling autobiography “ Rogue Warrior .” “He’s got a lot of upper-body strength. Long arms. Thin waist. Flat tummy.”

On this point, Greitens departs a bit. “You can’t make a lot of physical assumptions,” says the author of “The Heart and the Fist: The Education of a Humanitarian, the Making of a Navy SEAL.” There are SEALs who are 5 feet 4 and SEALs who are 6 feet 5, Greitens says. In his training group, he adds, there were college football studs who couldn’t hack it; those who survived were most often men in good shape, but they also had a willingness to subsume their concerns in favor of the mission.

The shooter’s probably not the crew-cut, neatly shaven ideal we’ve come to expect from American fighting forces. “He’s bearded, rough-looking, like a street urchin,” Marcinko supposes. “You don’t want to stick out.” Marcinko calls it “modified grooming standards.”

His hands will be calloused, Smith says, or just plain “gnarled,” as Marcinko puts it. And “he’s got frag in him somewhere,” Marcinko says, using the battlefield shorthand for “fragments” of bullets or explosive devices. This will not have been the shooter’s first adventure. Marcinko estimates that he might have made a dozen or more deployments, tours when he was likely to have run afoul of grenades, improvised explosive devices or bullets.

Chances are he’s keeping score. Smith, who served in the SEALs from 1991 to 1999, got together recently with five Navy SEALs, some of whom he’d served with and others whom he’d trained. “They were responsible for 250 dead terrorists,” Smith says. “They know their number.”

But there are terrorists, and then there are TERRORISTS. Bin Laden falls into the latter category. It’s hard to imagine someone not wanting to take credit for such a significant kill. Yet revealing SEALs’ identities would make them targets for al-Qaeda sympathizers and would also make it difficult or impossible for them to participate in future secret operations.

The identities of other key players in the war against terrorism remain anonymous. No one has identified the troops who slapped cuffs on Iraqi dictator Saddam Hussein or named the pilots who dropped the bombs that killed Abu Musab al-Zarqawi, head of al-Qaeda in Iraq. Times have certainly changed. Another era’s military history-makers were frequently publicly identified — Paul Tibbets, the pilot of the Enola Gay, the plane that dropped a nuclear bomb on Hiroshima, wasn’t a mystery. But this is a different kind of war — a kind of perpetual, amorphous conflict — one much less likely to see a formal declaration of peace. Also it’s likely the shooter’s superiors would forbid him and his colleagues to reveal his identity.

“This is playing in the Super Bowl and getting the Oscar all in one breath. He wants credit,” Marcinko supposes of the shooter who felled bin Laden. “But only among his peers.” Many SEALs consider themselves “humble warriors,” Greitens says.

But among his colleagues, the shooter’s identity will be well-known. And right now, he’s probably in for some locker-room-style ribbing.

“They’re gonna hard-ass him,” Marcinko says. “It’ll be, ‘If I’d have been there, it’d have been done in 20 minutes instead of 40 minutes.’ ” Smith can envision the shooter’s pals razzing him about the precise location of the shot. But, in the culture of the SEALs, it’s not as if he won’t push back. He’ll come back at them, Marcinko says, with something like: “Talk is cheap. I did it. I left my mark in the sand.”

There are sure to be awards and honorifics, all done in private. But the shooter is likely looking for some moments of peace, a way to completely remove himself from the pressure cooker. “These guys can one day be killing on the other side of the world and then mowing the grass 24 hours later,” Smith says.

But given the chance, he’ll almost certainly want to get right back into the action, to feel the rev of adrenaline again. “He keeps going,” Marcinko predicts. “He wants to prove that it wasn’t a fluke.” He’ll be thinking: “Let me prove I really did know what I’m doing.”

When the next helicopter is fueled and ready to whirl away, Greitens says, the Unknown Shooter will “be the first one running for the helo.”