Minh Matsushita was a man forever in motion, an adventure always in progress. His passport was a pocket-size accordion of pages bearing faded stamps and mysterious visas.

Even as his boyhood friends from the Bronx settled down, got married, pursued careers and started families, the 37-year-old Matsushita just kept reinventing himself. He might be a beach bum in San Diego one year and a tech geek in Manhattan the next. You could find him snorkeling in Australia, or hiking across minefields in Cambodia.

Dude, what are you doing?, friends would remember asking time and again, when he would alight between trips on someone's back porch to drink through the night and tell his tales. Minh always smiled, shrugged and gave the cavalier answer his buddies came to think of as his personal motto:

"No worries, man."

For the past 18 months, Matsushita had been living out the dream of the perpetual wanderer, exploring remote corners of the world as a tour guide for an Australia-based agency called Intrepid Travel. Leading tourists on treks through the jungles and paddies of Southeast Asia, he also found for the first time in his life something more than adventure.

He fell in love.

Rosie Cowan was a young Englishwoman and fellow tour guide with the same restless spirit and derring-do Matsushita embraced, someone whose idea of a good time might include locking herself into a diving cage to swim among great white sharks off South Africa.

When their respective contracts with Intrepid came to a close, Cowan and Matsushita decided to stop living out of rucksacks, for a while at least. She moved to London. A month ago, he followed. They found an apartment and reentered the real world. Matsushita quickly landed a job as a recruiter for an Internet company.

And then on a bright summer morning a week ago, he dressed in a blue pinstripe suit and set off on what should have been the most ordinary journey of an extraordinary life: taking the subway to work.

No one has seen him since.

Yesterday, the London coroner officially declared Matsushita dead, the lone American among 54 people presumed killed when a series of four bombs exploded July 7 across the capital.

A week after the attack, fewer than half of the victims have been identified, a delay police blame on the painstaking task of collecting and processing evidence from the twisted wreckage of buried subway cars, where they have found no bodies intact. There are only pieces that first must be photographed, then placed in body bags, then photographed again before being brought to the surface for closer examination and identification.

Waiting breeds reckless hope and useless anger. It convinces the friends of a missing hairdresser and the roommates of a lost Polish accountant that their loved ones survived and are wandering the streets of London somewhere with amnesia. It pushes the anguished mother of a young Nigerian oil executive to rail against terrorists near the bus stop where her son likely died. For a while, it made David Golovner think, wildly, that he could pack a miner's hat in his suitcase and join the search for his best friend Minh Matsushita beneath the streets of London.

For the past six days, Golovner, 36, hunkered with Matsushita's parents and two siblings in a borrowed London house, waiting not for a miracle, not even some undefined sense of closure. They waited instead for a death certificate. They wait now for a body to take back home.

They resigned themselves to Matsushita's loss soon after arriving in London on Saturday morning. Why else would police come to swab the mouth of his mother, Muoi, for DNA, to collect his hairbrush, his toothbrush, his razors, any ordinary thing they could find in his apartment that might yield Matsushita's fingerprints or genetic material? Why else rouse his dentist back in New York on a Sunday night to send records?

"We're all exhausted," explains Golovner, the designated spokesman, a political analyst for the Bronx borough president. Cowan is too shaken to talk about it, he explains. Matsushita's mother is starting to cook for the grieving household, a good sign, Golovner thinks. They're all longing to go home, to end this limbo part of it all.

His memories drift to other summer nights, when Matsushita, always the organizer even in high school, would plan keg parties in the park. It was never just a few kids and a single keg, Golovner remembers, laughing, "it would be, like, 10 kegs and a hundred kids." They had air-guitar contests.

"If we'd had a garage, we'd have been 'Wayne's World,' " jokes Golovner.

Matsushita never wanted the party to end. When they were older, he was the one always buying more food, ordering more rounds at the bar, just so everyone would stay longer.

"He'd come home and want to go out, and we'd all be, dude, we've got kids now!" Golovner says. Minh would shoot back, "Man, you guys are boring the hell out of me."

Reality set in earlier this week when Golovner went with Cowan's sister, Lulu, to the family assistance center authorities had set up in London. There was a white tent with tables and two officers inside. There were forms to fill out, questions to answer again and again. What was he wearing? Any jewelry, any wristwatch, any scars, any piercings? They were sent into the building, where another pair of officers asked much the same questions, in more detail. What color was the suit?

The details that would define Matsushita in death were flat and one-dimensional, predictable, prosaic, so very much not like Matsushita himself.

No one would know that he loved thick steaks and cheap beer and heavy metal music from the '80s and rafting on wild rivers. No one would know that he diverted tourists from the prescribed itineraries to introduce them to the kids he befriended in Cambodian orphanages. Or that he himself had fled war-torn Vietnam as a little boy with his widowed mother and the Japanese American businessman she would marry, Minh's adoptive father.

His family has set up a fund now to benefit the orphans, with Intrepid Travel promising to match any donations.

"He was amazed and bewildered that these kids who had nothing were always happy and smiling," Golovner says. His friends asked why he kept going back, why it didn't depress him. Matsushita struggled to explain how their pure joy made him happy, gave him hope. They had already found what he was searching the world for.

No one was surprised, really, when Matsushita decided to reinvent himself yet again.

That he traded his shorts and Tevas for a pinstripe suit.

That he traded grand adventure for great love.

That he would saunter off on a summer morning, no worries, and never return.

Minh Matsushita, killed in London, with Rosie Cowan.