On a hot June morning, federal K-9 officer Sgt. Isaac Ho'opi'i is speeding along Old Dominion Drive in McLean on the way to his job at the Pentagon when a deer jumps out and bangs into the right side of his police cruiser. The deer is hit in the shoulder, flips around, then regains her footing and bounds back into a leafy camouflage of trees and kudzu.

Ho'opi'i (pronounced HO-oh-PEE-ee) pulls off the road to check his banged up side-view mirror and calls out to the reporter who has been following him, "Hey, how's the deer?"

"I don't think you killed her," says the reporter, coming over to look at the damage. "How's the car?"

Ho'opi'i fiddles with his bent mirror and shrugs. "I'm not worried about the car," he says. He looks off into the thick tangle of woods. "I was afraid I hurt the deer."

Staring at the mangled mirror, the reporter says, "That thing could've gone through your windshield, could have killed you . . ."

The officer laughs, collapsing his worried look into a reassuring grin. At 5-foot-10 and 260 pounds, Isaac Ho'opi'i is a husky Hawaiian whose shoulders carry the strength of a Samoan wrestler. His large hands hang loose beside the weapon at his side, and his voice has the easygoing rhythm of the 50th state. "Well, a lot of things could have happened," he says, "but I don't deal in the couldas."

He climbs back into his cruiser and continues on his way.

Ten minutes later, Arlington's streets are filled with commuters and day laborers. Overhead, long green Army helicopters drone their way toward the Pentagon's heliport. In the back of the cruiser, a German shepherd prowls behind the metal screen separating the front and rear seats. Six-year old Marko bangs his tail hard against the seat, unshaken by the collision with the deer. The dog is protective of Ho'opi'i, but seems playful: one moment rolling on his back; the next, freezing statue-perfect at Sit!

In the trunk Ho'opi'i carries a three-gallon jug of water for the dog and two large photographs: a 1990s government-issue aerial view of the sprawling Pentagon and an "after" shot of the blackened rubble immediately following September 11, 2001. Rescue vehicles and cranes are scattered at the edges and an enormous American flag hangs vertically from the rooftop toward the ground.

"See all those trees?" Ho'opi'i points to a healthy stand of greenery opposite the heliport in the "before" shot. He remembers those trees because less than 15 minutes before the plane slammed into the building, he and his first canine partner had been standing there on duty. "The trees disintegrated the moment the plane hit."

At 8:30 on the morning of September 11, 2001, Pentagon Police Department Officer Isaac Ho'opi'i opened the back door of his car to let his big dog, Vito, out for a walk. Crisscrossing the Pentagon's manicured green lawn with his nose to the ground, the well-trained, black-and-red shepherd was unfazed by the noisy jets passing overhead on the way to and from nearby Reagan National Airport. Ho'opi'i followed Vito, his partner of three years, onto the tarmac of the heliport to let the dog sniff around for the smell of explosives.

Ho'opi'i says that headquarters had radioed him earlier that morning to let him know a high-ranking official was due to chopper in any minute. After Vito's inspection gave the all-clear, they climbed into the unmarked cruiser and headed away from the Pentagon to take Vito to the vet. Ho'opi'i recalls looking in his rearview mirror at Vito stretched out across the back seat and saying, "Good boy." With the sun dancing in silver slants between the Potomac River and the white monuments, it was just another spectacular September morning in Washington. And for the moment, Ho'opi'i knew, the Pentagon was safe.

"I was a mile away when I got the call over my radio: 'Emergency. Emergency!'" Ho'opi'i recalls. "Dispatch says, 'This is not a drill. A plane has crashed into the side of the Pentagon.' Huh? I was just there. 'Say again?' I flipped on my blue lights and siren and gunned my cruiser up to 130 mph. I blew out my transmission getting there."

One of the first rescuers to arrive on the scene, Ho'opi'i says he left Vito "barking like crazy" in the back of the cruiser and ran toward the smoke, ducking under live electrical wires and sloshing through jet fuel. "I went in and called out to people, and I could hear them calling for help," he says. "A wire was flashing sparks left and right. Smoke was following me and a sun ray came through like a path when I ran out" of the building.

Ho'opi'i is credited with carrying eight people out of the burning Pentagon. Some of the people he pulled from the inferno were alive, some were not. "It was an eerie feeling 'cause it smelled like jet fuel and it was pitch-black in there," says Ho'opi'i. "Voices were still there the first time I went in, but it was silent the next time. I found one woman burned really bad and put her on my shoulder. I brought her out to the tree lot and gave her to the medics. Some civilian guy looked at me and said, 'Hey, man, at least pull the lady's nylons up.' I felt bad about leaving her like that. Later the doc told me those weren't her nylons; that was her skin."

Those he couldn't see because of the black smoke, he tried to guide out using his deep baritone. Ho'opi'i stepped once more into the burning rubble and shouted, "This way! Come toward my voice!"

Survivors followed the sound as it led them out of the darkness.

Thirty-six hours later Ho'opi'i stepped through his front door with his eyebrows burned off. His wife, Gigi, discovered purple handprints on her husband's upper arms, where a burned woman wouldn't let go. Vito, who'd spent most of that time locked inside the cruiser howling wildly into the chaos around him, collapsed on the living room floor and didn't move for 12 hours.

In the nights that followed, Ho'opi'i couldn't sleep more than an hour at a time. Dark images of people trapped in billowing, black smoke rocked him awake in the middle of the night. He says he'd get up at 3 a.m. and walk down the hall to look in on his two sleeping daughters. "I'd say to myself, 'Thank God this house is peaceful and comfortable.'

"If I had at least one to two hours of sleep, then I'd just get up, get dressed, and automatically go to work. Everyone else was pulling double shifts, too. There was no time for feelings. I just tried to stay stable. I was more like just numb, not realizing I was just running like a time clock. For a long time I couldn't stop hearing the voices and seeing the smoke from that day. I felt guilty, like I should've brought more people out. If I'd gotten hurt, I would've felt better."

Gradually, stories began to emerge in the newspapers about a deep, accented voice that had led many Pentagon survivors out of the darkness. Other articles related Ho'opi'i's story about using his voice to call out to survivors trapped by clouds of black smoke. The survivors made the connection. On October 5, Ho'opi'i received a telephone call at his McLean home from William "Wayne" Sinclair, a civilian Army contractor from Riverdale, who had just been released from the hospital where he'd been recovering from second- and third-degree burns. Sinclair, 54, said he recognized the voice as soon as he heard Ho'opi'i speak. He told reporters, "I remember the accent. It all came back." After being positively identified as the voice, Ho'opi'i recalls, "a great weight lifted off my shoulders when I heard some of those people had survived."

John Jester, director of the Pentagon Force Protection Agency, says, "probably 18 to 20 people were saved on 9/11/01 when then-Officer Ho'opi'i told them to come to the sound of his voice to escape from the fire and smoke."

In newspaper stories around the world, the 38-year-old officer was hailed as a guardian angel. Ho'opi'i was inundated with newspaper and TV requests from the New York Times, to CNN, to the "Today" show. Over and over he told reporters, "I was just doing my job. I heard people crying. I couldn't not help."

On the floor of the U.S. Senate, Hawaii Sen. Daniel Akaka praised the officer's heroism, and in March 2002, Ho'opi'i was awarded the congressional Medal of Valor, the highest honor a public safety officer can receive. Upbeat and gregarious with the media, Ho'opi'i scrambled to make time for everybody who came calling. But in the back of his mind, he says, he kept asking himself: Was I really a hero? And regarding the people who didn't survive that day, he wondered: Why them and not me?

At the same time the media were swarming over him, Ho'opi'i was learning to cope with a different kind of attention. Off-duty and dressed in civilian clothes, he had been pulled over in his car twice by local police. With 15 years of experience on the force, Ho'opi'i says he understands how a guy who looks like him might set off a few alarms -- Ho'opi'i is a large, brown-skinned man descended from a long line of native Hawaiians, with a few seafaring Chinese and Portuguese ancestors added to the mix.

"9/11 has made everybody just a little more jumpy," he says. "Those cops are just doing their job. They wonder what this foreign-looking guy is doing, just driving around [Northern Virginia]."

The first time it happened, Ho'opi'i recalls, "The cop pulls me over and says, 'License and registration,' then he goes to check it out on his computer. He comes back, and I say, 'Can I ask you a question? Why did you stop me?' Cop says, 'Oh. There's been an attempted robbery nearby with a car that fits this description.' So I show him my badge and say, 'My name is Sgt. Ho'opi'i. I'm with the Pentagon police force.' Cop says, 'Are you armed?' Nah. I wasn't, so the cop says, 'Listen. I'm sorry. Hope you understand.'"

Ho'opi'i pulled his Jeep back onto the street, he says, and called the local police dispatcher to check out the details in that attempted robbery involving a black Jeep like his. The dispatcher checked it out, he says, came back on the line, and told him, "No. Nothing like that going on around here tonight."

Those first few months after the attack, Ho'opi'i and Vito worked extended security shifts of 16-hour days. Ho'opi'i says some Pentagon police officers walked away from the force after 9/11 because of trauma or fatigue and never returned. The Pentagon offered those who stuck it out free counseling. But Ho'opi'i didn't connect with a therapist. "We needed somebody . . . who talked our lingo, somebody who'd been there."

Instead, Ho'opi'i opened his heart to his trusted partner, Vito, who, like the other Pentagon dogs, lived at home with his handler. "I talked to him every day. I'd say stuff like, 'Hey, Vito, can you believe those [expletive] really took our planes and flew 'em into buildings?' He was a great listener. I could hear his tail wagging back and forth hitting the cage hard, meaning he was listening. Then I'd stop and think, 'Man, oh man. I'm talking to my dog.'"

Seven months after 9/11, on patrol one day, Ho'opi'i noticed the left side of Vito's mouth hanging loose, and soon the dog's floating prance had become three steps and a drag. He also began bumping into walls. After Vito performed poorly on his field training tests, Ho'opi'i took him to an Army veterinarian at Fort Myer. Her diagnosis was that Vito had had a stroke. As a result, Vito was immediately retired from the force, though he continued to live at the Ho'opi'i home. The split was hard on Ho'opi'i, he says, but still harder on Vito, who stood by the front door and wailed every morning when Ho'opi'i strapped on his gun and left without him. After that, Vito moaned and scratched at the door.

Finally, Gigi, a nurse, couldn't take it anymore. By the next week, "I started taking him to work with me on Tuesdays and Thursdays at the doctor's office," she says. "He was just happy to be back at work and around people."

Meanwhile, Gigi was worried about her husband; he was too quiet around the house, and their daughters Kukana, then 9, and Bess, then 18, missed hearing their dad's easy laughter. "It wasn't anything that anybody else would notice," says Gigi. "It just wasn't him. He wasn't as boisterous and outgoing as usual."

Another thing disturbed Gigi: Ho'opi'i, a musician in a local Hawaiian band, hadn't touched his guitar since September 11. "I assume he couldn't play because of his fatigue from working so much. Technically, it might have been called depression, but I think maybe he was still shellshocked. He was talking, and as a nurse I know that's the best sign. He wasn't so utterly depressed that he'd stopped eating. Now that would've have worried me. It's when they stop talking . . .

"I knew he'd snap out of it, but he needed some pushing -- a gentle shove, you know? Maybe the music was what he was missing in his life."

Inside the calm of the Ho'opi'i family's McLean townhouse, there are constant reminders of what the family has been through. Plaques, awards and commemorative photographs cover the walls leading up the stairs. Stuffed into a raku pot in the living room is the Olympic torch Ho'opi'i carried, accompanied by Vito, on the flame's journey to the 2002 Winter Games in Salt Lake City. A feathered spear presented by a Tongan tribal chief graces the hallway.

The winter after 9/11, Gigi invited over the other three members of the band -- the Aloha Boys -- to jam at their house, hoping the sweet glissandos of the laid-back music would be comforting for her husband. Ho'opi'i says, "I walked in and there they were. I said, 'No way! You guys are here for me?' I was still in my uniform. I went upstairs to change into jeans. I felt honored that they had taken the time to come over and do that." On that February night the four friends pulled their chairs into a kanikapila (jamming) circle to play their music, relax and shoot the bull. Gigi watched her husband run his fingers gently up the slender neck of his guitar and across its inlaid design, plucking softly. They sang their quiet melodies late into the evening before packing up their gear and heading home. Gigi had gone up to bed, she says, though she hadn't yet fallen asleep. Sometime after midnight, alone downstairs with Vito stretched out at his feet, Ho'opi'i began to play the familiar slack-key songs on the 30-year-old Takamine guitar his father had given him before his death. Gigi wept with relief.

Of that night, Ho'opi'i recalls, "I felt so refreshed. Besides, it made me see everything else in front of me, instead of just going to work with blinders on. It made me see this is what life is all about -- friends, family, and the aloha spirit. I remember looking over at Gigi standing in the corner and I was thinking: She was the one who set this up. That's exactly what I needed. She knew."

On a cold November morning in 2004, Vito, 8, laid his head down on the Ho'opi'i family's back porch and quietly passed away.

A few days after Vito's death, Ho'opi'i and Gigi decided to sprinkle his ashes at the Pentagon near where the plane hit. "It was after work, and I was off-duty," says Ho'opi'i. "We drove up to the Pentagon in our Jeep, so I called ahead to dispatch for permission to enter. That officer must have spread the word we were on our way because by the time we got there, five other K-9 officers had showed up with their dogs to tell Vito goodbye. Just to say what a great dog he was.

"If I had died, he would've laid down and died with me," says Ho'opi'i. "I still miss him."

These days Ho'opi'i brings Marko, Vito's replacement, into Washington area schools to do bomb-sniffing demonstrations. The officer says younger kids don't ask him much about what happened to America on September 11. It's the sleek, black bomb-sniffing German shepherd they want to see. On those visits, Ho'opi'i hides a tiny bag of explosive powder somewhere in the auditorium, then brings in Marko -- ears up, hair bristling along the ridge of his spine -- to search for it. Marko always finds it.

At 6 o'clock on a steamy summer morning, Ho'opi'i parks his cruiser inside the Pentagon gates and steps into Federal Office Building 2. Down a long corridor, Ho'opi'i takes a right into the headquarters of the Pentagon Police Department's K-9 division. Inside, four officers in their dark-blue uniforms get ready to begin the day. Their bomb-sniffing dogs wait outside in the officers' air-conditioned cruisers.

As time went by after 9/11, Ho'opi'i says, K-9 handlers in New York began to speculate that rescue dogs from the Pentagon and the World Trade Center disasters, like Vito, were incapacitated or dying as a result of their overexposure to chemicals, asbestos and stress. Studies done since then haven't supported that conclusion. Nonetheless, on 9/11 there were eight Pentagon K-9 teams, and from those teams, only two dogs remain on the force: Lt. Dennie Wayman's dog, Bennie, an elderly, long-faced German shepherd, and Robby, an 8-year old Dutch shepherd with dental "issues" -- he ate a doorknob. Sgt. Brian Mosley's canine partner, Ricky, was retired because of the dog's strange new fear of shiny floors after 9/11. Gliding along the slick, polished Pentagon corridors suddenly panicked him -- a liability for a dog whose job it is to protect the secretary of defense and visiting dignitaries in a city with miles of lacquered halls.

Pushing back from his desk at the K-9 division, Sgt. Bill Lagasse palms his blonde buzz-cut and lists the current whereabouts of the rest of his unit's 9/11 dogs. "Bak died of a twisted gut, Johnny's dead, Bill's being retrained for deployment to Iraq, Woody's with the Navy now, and of course, there's Vito -- now that was a gut-wrencher. Vito was a real friendly dog. Everybody loved him. That impacted everybody.

"Hey, we need the dogs more than they need us. Right after the attack, it sucked when you'd come to work and see the building smoking under the spotlights at 6 in the morning. It was the most angry, depressing bit of emotions -- and then you'd look in the back seat and see 80-pound Vito wagging his tail and sticking his paw through the cage, just 'cause he wants you to pet him.

"But during all that time I never saw any negative effects on Isaac," says Lagasse. "He didn't let it out here on the job. He just took care of it. He talked to Vito."

Ho'opi'i is walking along the same route he took after the plane crashed on September 11. Reminders of that day are everywhere. Along Corridors 4 and 5 in the E-Ring of the enormous complex, there are, overhead on a long wall, handmade quilts with keepsakes -- letters, photos, bits of fabric -- of lost loved ones, and promises to never forget them.

On 9/11, clouds of billowing black smoke filled these corridors, blinding scores of military and federal workers, who could not locate the exits. Today, stretching along the baseboard just inches above the shiny floors, newly installed glow-in-the-dark illumination arrows point out every step to the nearest exit. "Smoke rises," Ho'opi'i explains. "And people tend to crouch down to find their way out."

Ho'opi'i pushes through a pair of heavy oak doors, paying no notice to a prominent plaque bearing his name hanging on the opposite wall. He enters a cool, dark chamber situated next to a silent, empty chapel. On a corner table, a crisply folded American flag rests under glass in a triangular wooden frame. This flag once draped the casket in which the remains of some of the unidentified victims were buried.

Ho'opi'i comes to a standstill before a large black marble wall. This is the point of impact, exactly where the plane hit, and where today the names of 184 men, women, and children are engraved. Officially, the death toll on 9/11 was 189, but the Pentagon memorial excludes the five terrorists.

Ho'opi'i slowly reads through the names until, tracing his finger gently over one, he stops. "I knew five of the people whose names are here -- because they all loved to stop and talk to Vito. Like this lady . . ."

His finger rests under the name of Army Lt. Col. Karen Wagner, a 40-year-old medical personnel officer who lived in Alexandria.

"She used to bring treats for Vito," he says. "When she'd see us coming, she'd kneel down and scratch his head like an old friend." Ho'opi'i smiles at the memory. "Gradually, I was out of the picture all together."

Ho'opi'i turns away from the names and steps over to a window, looking out across the Pentagon grounds at a vivid canopy of green shrubbery, planted to replace the trees that disintegrated when American Airlines Flight 77 exploded.

He leans his hefty body against the windowsill and runs a hand across his face. A full minute passes before he speaks.

"A while back I was doing traffic control after a 9/11 memorial service. A man comes up to me in the middle of a real busy intersection, and he starts introducing his kids and his mother-in-law. He was crying, saying his wife died on 9/11, and he just wanted to thank me for whatever help I may have given her that day. Cars are zooming by everywhere. I took the whole family over to a grassy spot -- a safe place -- on the side of the road beside my cruiser." Then, Ho'opi'i says, he opened the back door to retrieve Marko and led him over to the family. "And for the longest time they just sat there crying, you know -- petting the dog."

Glen Finland is a writing professor at American University.