Officer Larry Greene looks at the crowd on the corner and knows the enemy is here. After dark, near 14th and U streets in the heart of the city, somewhere in this street-corner gang is the addict and the pusher, maybe even the thief, the mugger, the armed robber, the rapist, the murderer.

Almost instinctively, Greene grabs the microphone from beneath the dashboard of his battered police cruiser, turns up the volume so that the voice of authority will resound down the street, and issues an ultimatum. "The Po-leese!" he cackles. "All of us Sasquatch team is out! Let's clear it. . . . "

Some people move along, most stay. There are 100 or more, six and seven deep along the sidewalk this night in December. Greene and another officer survey the field, picking their targets: the one wearing a red jacket and white hat, the one with a black skull cap and blue jeans, the guy with a tan waistcoat.

Moments later, the two officers enforce the law--their law, their way. They wheel their car to the curb, sprint into the scattering crowd, nab the three preselected suspects, escort them back to a transport cruiser, drive them to the police station, charge them with blocking the sidewalk, threaten them with $50 fines, collect $10 on the spot in a makeshift plea bargain and let them go.

Sasquatch, as the raid is called unofficially, is named after the legendary big-footed creature of the Pacific Northwest. In the two square miles that comprise the 3rd Police District in Northwest Washington, the big foot belongs to the police. Greene says a dozen officers have made hundreds of Sasquatch arrests in the last year and records show that there were 62 on eight days alone. The officers have dubbed their $10 fine the "Northwest Sidewalk Tax." They call their hall of justice "3-D Court." They enact the law on the street, then prosecute and sentence in the cellblock of their station, with no judges or lawyers to get in the way.

"What about their constitutional rights?" a colleague once joked with Greene, as street-cop justice was about to be administered.

"What Constitution?" came the reply. "That only goes for straight people, ain't it?"

Every day, on the streets of the 3rd District (known as 3-D), the police encounter hordes of drug addicts who buy heroin known as "Murder One" and "Black Tape" at $40 a packet in public view, right in front of children--some of whom get injured by discarded needles, right in front of working people waiting for the bus, right in front of old folks walking down the sidewalk with their groceries.

To Greene and some of his fellow officers, these junkies are an occupying force, immune to traditional methods of law enforcement and protected by the criminal justice system that seems to allow them to return to the streets even before the paperwork is done. These officers resort to less traditional means--the roundups, the mock courtroom at the cellblock, the informal plea bargain resulting in a permanent arrest record.

"It's harassment. I'll even admit that," says Greene. "[The junkies] are harassing the good citizens. The only thing we can do is harass them right back . . . . The government took all our tools away." Reasons one of his bosses: "If we went by the book every time, we would lose control out here."

For Greene, the "book" is only a guideline--"all it is meant to be"--in his daily struggle for control of the street corner. Not everyone who reports for duty at the red-brick precinct station at 17th and V shares his approach. Yet they all share his concern as they patrol the most compact, intense and--block for block--violent of Washington's seven police districts.

Here, in one year along 200 crowded blocks in the center of the nation's capital, from Harvard Street on the north to L Street on the south, from Connecticut Avenue on the West to Fourth Street on the east, the latest statistics show there were 36 murders, 856 assaults, 1,347 robberies and nearly 10,000 arrests--all either the worst or second worst crime figures in the city.

"Every night is Saturday night," says Bernard Crooke, a former 3-D commander. "If you can police in 3-D, you can police anywhere in the United States."

The street cops who patrol this one small pocket of downtown protect 70,000 people--some of Washington's poorest (along the 14th Street corridor and in the Shaw neighborhood), some of its richest (near Dupont and Logan Circles), and some of its newest (along Columbia Road where Hispanic immigrants have settled in large numbers). Their runs take police to fancy hotels and prostitutes' "trick pads," to foreign embassies and soup kitchens.

The problems are different from one block to the next, and never cease. One veteran likened his tour in 3-D to "20 years of combat duty." The 380 officers assigned to the district must constantly adapt, rebound and improvise as they move through the dense and disparate streets. Their world has produced its own code of justice. And it has produced Larry Greene.

The former Vietnam tank commander's official assignment covers 17 blocks, touching the northwest side of Logan Circle. But Greene is forever dashing up and down 14th Street from Thomas Circle to Chapin Street. The 32-year-old Greene lives on only about four hours of sleep a night and, at times, seems as weary of the street people as they are of him. After 10 years, he is fed up with 14th Street, tired of that narrow crime-ridden strip he calls his "trouble alley." At times, he says, he wouldn't even mind being injured if he could retire on disability.

Still, Greene has the energy of a rookie in the body of a veteran. He has eaten too many dinners of candy bars and Cokes. Like many officers, he has arrested many people in 3-D more than once. He feels he can tell who is innocent and who is guilty merely by how they act. He believes "revolving-door justice" swings back to hit police officers first. He has a crisis mentality; his first priority is survival.

"There's federal law, there's District law, and then there's my law," says Greene. "I'm about the formalities later."

He is the quintessential "bad boy" cop. He badmouths his superiors, and they badmouth him back. He exceeds the speed limit, and he gets caught for it. He runs into crowds of junkies saying, "I'll lock you up just for being!" (His colleagues remember another officer who provoked junkies and was killed by a drug pusher two years ago.) Greene, who suffered a fractured skull and broken finger last year in fights with suspects, feels that a nonaggressive officer has his "tail between his legs." He has been in more than a half-dozen scout car and motor-scooter accidents, and when he was admonished for receiving too many citizen complaints, he claims he went on a one-man work stoppage for two years, answering only easy calls and making few arrests. Later, when he again felt the support of his superiors, he renewed his old drive. " 'Bout time you started locking people up," he recalls his sergeant saying, welcoming him back.

An officer like Greene survives at 3-D in spite of himself. Greene is an exception whose exploits are viewed with both admiration and disdain. Yet he is tolerated and his productivity makes his bosses look good.

During several weeks this year, Greene made a dozen arrests, stopped a rape in progress, helped solve a kidnaping, and organized several Sasquatch roundups that produced a drug informant, a murder suspect, illegal handguns, and narcotics. He also resuscitated an overdose victim, mediated several family fights, counseled a child playing with matches and sent a drunk man home in a cab.

He races down congested streets, whipping Car 98 around turns and crashing over unexpected bumps. He has been known to speed down 14th Street on winter nights when the road is icy, hit his brakes hard and skid "98" in rapid but graceful pirouettes. Greene calls them "Double Donuts." Some colleagues have named him "M.O.," for "mental observation" case. To a few, at least, it is a term of endearment. "I know the way Larry drives, and I hope when I get my a-- kicked, he drives his a-- off to get there," says officer Russell Brigham.

Greene's nature has translated into something much more fundamental: He usually is the first to arrive on calls and few officers have a better reputation for backing up their colleagues. Other officers await his arrival on dangerous missions.

"Greene is everywhere," said officer Harold Wooten. "There's a shooting, Greene is there. There's a stabbing, Greene is there. He's always on the scene. You begin to wonder who is this guy or how many are there?"

One night, when there were not enough officers to run a Sasquatch roundup, Greene drove his car onto the sidewalk, scattering addicts. "That's exactly what I think of them--animals," he says. "I'd just like to shoot 'em and get rid of 'em all." But several weeks later, Greene was on Swann Street, saving a heroin addict's life.

Her name was Juanita. She had overdosed on heroin and lay unconscious at the top of a narrow flight of stairs. Greene started to work on her. He slapped her side. "Come on, baby, don't forget how to breathe," he said. "They forget how to breathe," he explained to the girl's mother. He continued to slap her side. He told a child to fetch some snow. "Come on, baby, breathe!" Greene said. He sprinkled the snow on the woman's stomach and around her neck and rubbed it in. Soon, there was a deep, rumbling sound and the woman roused. When an ambulance arrived, Greene was credited by the medics with saving the woman's life. "Juanita," the woman's mother said as she was led off to the hospital, "You thank this man, he's police . . . . "

"He's always doing it. He thinks he's a medic," said Geraldine Stewart, Greene's long-time partner. Greene's trunk is filled with bandages, hospital tape, peroxide, and distilled water. In April, he was driving to another call when a stabbing report came over the radio. Greene detoured to the scene, examined the victim, wrapped her in tape and gauze, and left for his original assignment. When other officers arrived, they were baffled to find their victim already treated.

Greene's relationship with Stewart is as strong as a sibling's, despite a less-than-promising start. At their first meeting five years ago, Greene thanked Stewart for helping him with some paperwork by patting her thigh. She hit him in the face.

Eventually they reached an understanding. "We became the best of friends," Stewart says. Greene helped ease her through difficult times. A black woman raising children alone, Stewart recalls feeling out of place in a policeman's world: "Everyone was looking at me to run away from a fight or not to defend them." Other officers harassed her and labeled her a "honkie lover." One night her tires were slashed. Greene was furious. He gave her money to repair the car and confronted the officer responsible for the vandalism. He gave her emotional support; she cooled his hot temper. Stewart recently was transferred inside the station, and Greene eagerly awaits her return. "I wouldn't trade her for anybody," he says.

Twenty-five years ago, the 14th and U area was thriving with nightclubs that featured celebrities such as Duke Ellington and Ella Fitzgerald. The political fabric has been just as rich: Stokely Carmichael's Student Non-violent Coordinating Committee was located here, as was Pride Inc., the black grassroots organization that helped launch Mayor Marion Barry's career. But over the years after the explosion of 1968, the riots and looting, many merchants fled the area. Parts of the neighborhood are gradually being rebuilt now, but the corner is still essentially a decaying, burnt-out shell with abandoned buildings and a legacy of drugs.

Sasquatch began here more than a year ago when a man approached Sgt. Joe Williams in his police car. "Officer," said the man, "I am so glad to see you here. This is the first time I didn't have to ride an extra stop to get off the bus."

Williams recalls: "The crowd was so big he'd ride a block out of his way . . . . People have a right to be able to get off at a bus stop without being in fear." He ordered Greene and others to begin issuing warnings and locking up people.

Thus began Sasquatch. "The name is mine. I gave it," says Williams. "There's no big problem with it and the main thing is to be sure you're not getting anyone who may be innocent." The officers eagerly carried out the mission. They started enforcing the city's rarely used "incommoding" law, a regulation that prohibits people from blocking the sidewalk.

The key to their enforcement has been repetition. "When we feel like it, we go down there and hit 'em, handle a couple of them, then hit 'em again," explains Greene. Sometimes "the whole block goes."

Records show there were 40 Sasquatch arrests on seven dates in January and 22 last Thanksgiving Day.

At the precinct station, the suspects are offered the standard Sasquatch plea bargain: Leave 14th Street until morning, the incommoding charge will be reduced to disorderly conduct and the $50 fine to $10--to be paid like a parking ticket. The police cannot remember anyone refusing the offer.

Most officers involved in Sasquatch agree that it does disperse crowds. But enforcement of the incommoding law in this way is questionable. Police regulations state: "The incommoding laws were not intended . . . to keep . . . 'undesirables' moving or to keep groups of people from gathering . . . Here the streets are for people . . . all the people--even 'undesirables,' as long as they are not breaking the law."

"There ain't no way in hell you can tell me they are doing anything they're supposed to be doing," says officer Thomas Childs. "The officers are trying to take it on themselves to help out the community, so the kids can walk the street, so the ladies can get on the bus unmolested."

The officers also point out that their Sasquatch roundups turn up illegal guns and other weapons, illicit drugs, defendants wanted for more serious crimes and new police informants.

Not all of the officers who take part in the Sasquatch raids are as enthusiastic as Greene. "I'm involved because my partner wants to be involved," says one veteran who requested anonymity. "I'll watch . . . I don't really approve of them and don't know how legal they are. I get the feeling some of those caught up there weren't those they gave the warning to."

Under police rules, officers must first give a warning, then allow a several-minute grace period before moving in to make the arrests.

Wayne Simpson, a muscular officer who moves through the crowds like a one-man wrecking crew, takes a few steps back if he doesn't like the way a Sasquatch is being executed. "That wasn't done right," he said after one roundup last January. "There was no warning. [They] didn't give them [time] to go nowhere."

Although Simpson faithfully backed up his colleagues on the street that day, he chose to wait in the 3-D lobby until the arrests were processed. "If I feel something is shaky," he says, "I'd rather stand off than get involved. It's just my way of doing things."

Sasquatch ended several months ago, according to Greene, although 3-D officers continue to conduct roundups to disperse the crowds on 14th Street.

December 28, officer Dale Hughes drives to the corner of 14th and U and sees a crowd that stretches from Pamela's Deli to the Republic Bar. He nods disapprovingly and asks: "What is this bull----?"

Greene takes it as a signal that it is time for action. "I got a run," says Greene, "and then we'll come back and Sasquatch."

About a half-hour later, Greene is back. Hughes is gone, but another officer, Wilson Barreto, is here.

Sometimes Greene begins with a polite "Good morning, gentlemen. Don't block the sidewalk." Other times he warns sternly: "If I catch you twice, you'll pay $50 to Mayor Barry's reelection campaign."

Tonight Greene announces simply over the PA system: "Quit incommoding the sidewalk or it'll be $50." He scans his audience, saying to himself, "I got to pick me someone."

Greene settles on a man with a red parka and white hat and makes mental notes of the man's clothing so he will remember. Barreto makes his selections. They circle the block and race back. With a third officer backing them up, they make three arrests. Each officer takes credit for one.

At 3-D, two of the three prisoners admit hearing Greene's warning. "I heard, I heard," one says.

"You get out of town--I'll drop it down to $10," Greene proposes, making the standard offer. Both prisoners accept.

"You won't catch me up there no more," the second man says.

The third prisoner, frail and elderly, sits quietly. His hands shake slightly as the cuffs are removed. He unfolds a wallet and gives Greene some identification. His name is Walker. He says he is a laborer who had been waiting to catch a bus to visit a relative when the police had arrested him.

Greene notes that the man is 57 years old. He believes Walker. "Not a needle mark on him, and junkies never live that long," Greene observes. It appears they caught an innocent bystander in their Sasquatch. Greene practically orders one of the other prisoners to help Walker: "You pay him out."

The other prisoner shakes his head. "Ain't this something. I'm going to call the Better Business Bureau," he says. But he agrees to pay Walker's $10 fine in addition to his own. No matter who pays, Walker's name remains on the arrest book.

"I'm thankful that I'm out, sir," Walker says. He has not realized that in his case merely standing in the wrong place at the wrong time in the 3rd District resulted in a permanent arrest record.

Greene puts Walker in the back seat of his cruiser and drives him back to the bus stop. As Walker steps out, he again thanks Greene. "Have to use somebody to be an example," he says. "I understand."