As dusk falls in North Philly, armies of hoodies appear on West Thompson Street, their faces framed by shadows. This part of town hasn't been remade by real estate speculators. Vacant lots are strewn with crumbling bricks. A speakeasy runs out of a basement, with dollar drinks and hookers. Sidewalk dice games go on all night.

Dwight Dixon, a 5'11", 280-pound ex-convict with a big mouth, is a magnet for the kind of trouble that keeps so many buildings boarded up around here. On April 29, 2008, he was standing outside a take-out joint on the corner of West Thompson and North 25th streets when it found him again. Two weeks earlier, at a local bar called Playmakers, he'd gotten into a beef with a man he'd known since childhood. Now here that man was, right beside Dixon, wanting to collect an apology. Within seconds, the two were jawing, then trading kicks and punches. "I was getting my ass kicked," Dixon says.

Even after onlookers broke up the brawl, Dixon was hot. He jumped into his Toyota truck and jammed it into reverse, driving the wrong way up West Thompson as he shouted, "You just think you can go 'round doing what you want to people?"

After Dixon stopped his truck in front of Chuckie's Garage to argue further with the man, a shot rang out and a bullet ripped through his hand as it grasped the steering wheel. "Bullets were flying past my head, all over the car," Dixon says. One shattered his rear window. Another went through his jeans, just missing his leg. Others sailed down the street, shattering the windows of a Mercury sedan with a 2-year-old boy and his father inside. A bystander was struck in the back.

Dixon sped away on blown-out tires. In the rearview, he says, he saw the man who he claims shot him, Marvin Harrison, giving chase, running every bit as hard as you'd figure a future Pro Football Hall of Famer could run.

We expect our heroes to let us in, to show us more than their game faces. But over the course of Marvin Harrison's 13 years in the NFL, the Colts receiver has built an All-Pro career behind a firewall of privacy. Quiet precision defines his every move. On the field, he starts each route identically, forcing defenders to guess where he's headed. In the locker room, he sits facing his tidy booth, away from the media and teammates. At home, he keeps each touchdown ball he's ever caught in its own box.

On the rare occasions when Harrison offers a private thought to the public, he quickly clams up. He once told a Philadelphia Inquirer reporter that he loved Anita Baker—then refused to divulge his favorite song. When asked to comment for this story, he declined, as did the rest of the Colts organization. ("We're going to honor Marvin's wishes," said a spokesman.) And when Harrison made his 1,102nd career catch, on Dec. 28, moving him into second place on the all-time list, the wideout simply trotted to the sideline, ball under his arm. During an ovation from 66,721 fans, he sat alone at one end of the bench. He accepted a hug from head coach Tony Dungy but said nothing—then or after the game. "Marvin has a force field around him," says former Pro Bowl defensive end Marcellus Wiley, who played in the NFL for 10 years. "He's the guy leaning against the wall, not dancing, while everyone else boogies to their favorite song."

Before Super Bowl XLI, reporters asked Peyton Manning about his receiver's reticence. The QB said he didn't know Harrison well until he visited him in Philly one off-season. "There's a Marvin in Philly and a Marvin in Indianapolis," he said. Even around his teammates, the Indy Marvin barely says a word.

To be fair, Harrison owes fans and teammates nothing beyond his best efforts on the field. But the more he leaves blank, the more we fill in. He flashes no bling, no gold teeth. There are no Sharpies and no whining. What products does he endorse? Who is he dating? We have no idea, so we ascribe to him the qualities he shows in games and of those around him—the earnest indefatigability of Manning, the quiet strength of Dungy. For fans, this trio personifies old-school virtues: the Colts as color-blind, hardworking winners.

But that, as it happens, may say more about us than about No. 88.

Harrison was raised at North 24th and West Thompson streets, a block away from where he would brawl with Dixon. He was 2 when he lost his father, who died at 22, reportedly of natural causes. Marvin was 12 when his mother, Linda, moved him and his sister to the middle-class neighborhood of Roxborough, in Northwest Philly. As Marvin watched her work two jobs, he developed the values we'd later prize in him: discipline, reserve, thrift.

Even Manning has said that there are two Harrisons: the Indy version and the man from Philly. Harry How/Getty Images

At Roman Catholic High School, where he emerged as a two-sport star (the other was hoops), Harrison wore a tie every day, rarely missed class and studied to boost his grades so he could get into college. He became a huge star at Syracuse but never talked a big game. In fact, he barely talked at all. "We spent a lot of time together," says Cy Ellsworth, an Orange lineman who used to hitch rides to Philly with Harrison. "But I still can't tell you that much about Marvin. There was a side to him he didn't let people invade." On the day of the 1996 NFL draft, Harrison watched as three receivers were chosen ahead of him. "I have to get a job," The Washington Post quoted him as saying over and over that day, before the Colts took him with the 19th pick.

His career in Indy, where he lives alone, has played out better than anyone could have hoped. But Harrison never really left his old neighborhood, treacherous as it is. According to a local watchdog police group, 323 "serious incidents" were reported in the area in 2008. "We bury three or four kids every year," says Angel Colon Jr., program director at the Daniel Boone School, a local disciplinary academy. Talk to the folks around West Thompson Street—the owner of Lorenzo's take-out, the woman at New Beginnings Day Care, a cop on the beat—and they'll say they've seen Harrison within the past few days. Even during the season he spends most Tuesdays back in Philly.

More than nostalgia brings him back. Over the past six years, Harrison has been buying up his childhood stomping grounds. In 2003, he acquired the West Thompson Street garage now called Chuckie's for just $10,210. The next year, he added a bar a few blocks away, on North 28th Street, which he runs as Playmakers—the place where his feud with Dixon began. In all, Harrison owns 20 North Philly properties, many clustered around the block where he once lived. And he is no absentee landlord. Kids on their way to school recently saw Harrison fixing the shutters on one of his places. In contrast to other stars who've invested in urban real estate, though, Harrison hasn't announced grand revitalization plans. The businesses he supports—the garage, the bar, his mom's Italian restaurant, his aunt's soul food place—are neighborhood joints. And while he's well-known in the area, he isn't known well. The Daniel Boone School invited him to talk to the kids a few years back, but he declined. His name graces no community center or local gym. "I haven't been able to get to him," says Steven Williams, a community-development exec.

Actually, all it takes is a trip to Playmakers on almost any weekend that the NFL isn't in session. Harrison works the door of his own bar, patting down patrons and tossing those who are packing. To most of us, it's an inconceivable tableau: Marvin Harrison, King of West Thompson Street?

For years, though, Harrison has offered clues that he is serious about protecting his turf, and a more complicated man than we see in games. On Jan. 4, 2003, before kickoff of an AFC wild-card game at the Meadowlands, Harrison was catching passes from Manning as Jets ball boys shagged punts from New York's Matt Turk. One of them, a 23-year-old Long Islander named Matt Prior, threw a ball downfield that bounced near Harrison. According to a New Jersey Sports and Exposition Authority report—and two people on the field—No. 88 felt the toss violated his personal space. He charged Prior, bumping him in the chest.

"You threw the ball at me!" Harrison screamed. "You're a professional! You should do your job better than that!" Everyone on the field froze. Prior asked Harrison to back away. Instead, Harrison grabbed Prior by the throat and lifted him off the ground. While fans watching on the stadium's video screen chanted for their ball boy to fight back, players and workers tried to separate the two. As Harrison argued with security, Prior was taken to a medical station, where marks were found around his neck. "This was a violent incident," says Dan Santos, security manager at the Meadowlands that day. "Coaches tried to downplay it, but we were one step from making an arrest." In the end, though, Prior decided not to press charges; he just wanted an apology he never got. The NJSEA referred the incident to state police, who didn't pursue it.

That wasn't the only time Harrison drew looks from law enforcement. On the evening of Feb. 10, 2005, three nights before the Pro Bowl, he and two men were walking along a row of stores at the Hilton Hawaiian Village hotel in Honolulu. According to a police report—and a witness—Harrison was talking on his cell when a group of teenage fans asked for his autograph. Harrison declined, and when the fans kept pestering him, he and his friends turned on them. The Pro Bowler took a swing at one fan, then grabbed him by the throat and put an arm around his neck. After more scuffling, Harrison and his friends ran off, leaving one of the teenagers beaten. "I was walking about three feet behind these kids," the witness told The Magazine. "Harrison and his friends acted like real punks."

Despite the police report, Honolulu's prosecuting attorney didn't press charges. "We couldn't prove them beyond a reasonable doubt," says deputy prosecutor Renee Sonobe Hong. And once again, hardly anyone took notice.

After news broke of the shooting in Philly, it was easy to believe Harrison when he said he had nothing to do with it. It was hard to imagine No. 88 shooting at a man, even harder than it would have been to imagine him beating up an autograph hound or ball boy. While fans, reporters and New York's mayor pilloried Plaxico Burress for going into a nightclub with an unlicensed gun, Harrison continued to hide in plain sight, saying nothing, letting us view him as we wanted.

Turns out, Harrison also knows his way around guns. After a tipster called cops on April 30 to say "You should be looking at Marvin Harrison for that shooting on West Thompson Street," police matched five shell casings found at the scene with a model of gun registered to Harrison: a Belgian-made semiautomatic pistol that fires bullets that pierce 48 layers of Kevlar. This is military-grade bling, favored by connoisseurs because it is easily concealed.

When police paid a follow-up visit to Chuckie's, they found Harrison sitting in a beach chair near a cardboard cutout of himself in a Colts uniform. They asked if there were any guns on the premises, and to their surprise Harrison lifted the leg of his jeans to reveal a registered .22-caliber handgun strapped to his ankle. Soon after, a man whom Harrison called his stepfather handed over the Belgian pistol, fully loaded.

That night, Harrison drove to the police station to answer more questions. He seemed relaxed, nonchalant. Over the course of two hours he admitted to the fistfight with Dixon but insisted that the gun he'd turned in hadn't been in Philly the day of the shooting but at his suburban home, a half hour away. He said he hadn't fired it since buying it two years earlier and told the cops the same thing he told the Colts: He had nothing to do with the shooting on West Thompson Street.

The father of the 2-year-old in the shot-up Mercury sedan wouldn't talk about the incident. Dixon wasn't much of a witness either. Cops charged him with lying to the police after he gave bogus accounts of what happened. He had good cause to keep police in the dark: He was on parole for a drug conviction. Only after police told him further ballistics tests proved that five bullets fired that night exactly matched Harrison's gun did Dixon settle on one version. According to a police source, he told detectives the story that put the gun in Harrison's hand. (Dixon later sued Harrison for $100,000 in damages.)

But Robert Nixon, the bystander shot in his back that day (the bullet remains in his shoulder), apparently had no issue with talking to the cops. According to a police source, Nixon told detectives that he saw Harrison with a gun in his hand during the fight with Dixon. And while other elements of his story occasionally varied, police believed his account enough to place him in protective custody for two weeks after he came forward.

Still, on Jan. 6, Philadelphia district attorney Lynne Abraham announced that her office won't be bringing charges against Harrison at this time. "I'm pretty comfortable I know who fired the gun," Abraham said, but later explained, "I have to prove a case. With these witnesses, I don't think so."

In the end, the seeming contradiction between Harrison's statements about his gun and ballistics tests placing the gun at the scene were not enough for Abraham to move forward. So Harrison can sit back in his beach chair on West Thompson Street and keep watch on his block.

Meanwhile, around the Philly courthouse, the case still has buzz. "What do you think about the Harrison case?" a clerk recently asked a cop in the case. The officer did not hesitate to answer.

"Looks like Marvin caught another pass."