For months now, everybody's been wondering:

     Where's Osama bin hiding?

     Now, as Northern Alliance and US special forces close in on what the believe is the fugitive terrorist's hideout in the mountain complex at Tora Bora, they face a new challenge. 

     How will they know if they have the right guy?

     In the three months since his henchman attacked America, the 44-year-old bin Laden could have done anything from escaping to Yemen to having his physical appearance altered through plastic surgery.

     Defense Secretary Donald Rumsfeld has even suggested that the United States may never capture the Islamic extremist. 

     But former intelligence officials, terrorism specialists, fugitive hunters and medical experts said yesterday the government has the means to identify their elusive target under almost any circumstances, dead or alive.

     "I'm sure they have fingerprints, they certainly have pictures and they probably have DNA if they need it," said Frederick Rustmann, Jr., a former head of the CIA counterterrorism station abroad, who now runs CTC Group, a Florida-based business intelligence firm.

     "That’s not as important, though, as the intelligence that will come from someone who will tell them, "He's in that cave.'"

     Rustmann said any intelligence profile of bin Laden would include all vital physical statistics, from the basics of height and weight and eye color to any identifying scars or health problems. 

     The left-handed bin Laden, for instance, is believed to require dialysis for kidney failure and is also suspected of having heart trouble. Some medical experts also believe he suffers from Marfan syndrome, a debilitating connective-tissue disease that may be the reason he has been photographed walking with a cane.

     The terror mastermind's greatest identifying trait may be his height. Standing somewhere between 6-foot-4 and 6-foot-6, he is head and shoulders above many of his Afghan followers.

     "He'd love to become shorter, I'm sure," said Rustmann.

     "I just hope they arrest anyone crossing the Afghan border over six feet tall."

     Terrorism expert Stephen Gale of the University of Pennsylvania says it is possible that the Saudi-born bin Laden has made it out of Afghanistan and is now in the mountains of Yemen, where his family has roots that go back generations.

     "He comes from an area of Yemen where if you go, you feel like you stepped back in time," said Gale, who earlier worked with US government agencies and a defense contractor.

     "It's an extremely conservative Islamic society. He wouldn't be circulating, but he could easily disappear." 

     According to the FBI, bin Laden has used a number of aliases to disguise his identity, including "The Prince, The Emir, Abu Abdallah, Mujahid Shaykh, Hajj" and "The Director."

     But there isn't much he could do to his appearance to give him more cover.

     "I think he knows it wouldn't work," said Gale. "Cutting his beard leaves him a beardless 6-foot-6 man, which is just unbelievable in that society. I don't think he feels he could go incognito - maybe if he were 5-foot-6."

     Rustmann agrees. "I don't think he's going to try and sneak across the border in a dress or anything," he said.

     Cosmetic or plastic surgery can turn the clock back and enhance special features, but it can't make you look like a completely different person, said Dr. Raphael Gabay, founder of the Gabay Cosmetic Surgery Center in Northeast Philadelphia.

     Few experts interviewed expect that US troops will identify Osama bin Laden while he's alive.

     First there's the reward money on his head - dead or alive. Perhaps enough to turn up informants with good information on bin Laden's whereabouts - and people who would know him if they saw him, nose job or not.

     "Let's not forget there's 25 million American dollars out there for informants," said noted New York private investigator Beau Dietl, who just hired Philadelphia Police Commissioner John Timoney.

     "I think when he gets shot in the head, he's gonna look the way he looks to us now."

     Rustmann had no doubt that the US will find bin Laden, no matter where he's hiding and what he looks like. For now, his intelligence connections tell him that the terrorist is indeed occupying the bombed-out Tora Bora mountain hideout.

     "I think the most likely scenario is we'll never see him again alive," said Rustmann.

     "If we find him, we'll find him dead. If we don't he'll still be dead" in some kind of cave or bunker collapse, he added.

     "His fate is to be a martyr," said Gale. "I don't think he wants to be captured."

     Like Rustmann, Gale believes that even if bin Laden is found alive with a group of his followers, the orders will be to shoot first and ask for passports later.

     Then identifying Osama will be easy. Much more difficult, say the experts, will be identifying and apprehending the members of the 30 or so independent groups that make up his terror network. 

     "There are two in the US and we don't know where they are," said Gale. "There's one in Toronto, and London and France and in Germany. It's a snake with many heads."