Then the telephone rang again -- and again. Each time Mike picked up the receiver to hear the same animal-like scream. Toward daybreak, the caller asked for someone by a name that made no sense.

Before dawn the telephone rang at the Coxes' house in Dorchester. Mike turned carefully and grabbed for the receiver by the bed. He heard a voice grumbling. The voice was unfamiliar, and Mike had to hold the receiver away from his ear when the grumbling grew into a primal scream. Then it stopped. The caller hung up. Mike was puzzled, but didn't think much of the weirdness. He and Kimberly tried to get comfortable again.

On Friday, February 3, nine days after his assault, the first newspaper story ran mentioning Mike in connection with the capture of four murder suspects. The Herald's early bulldog edition hit the streets not long after midnight and was usually read by the cops, firefighters, cabdrivers, and anyone else working in the dark. The story said Mike had been injured and the department was investigating whether he'd been beaten.

Mike was figuring that within days he'd hear from the cops who'd beaten him. He was counting on an apology. "I expected the individuals to come forward and say what they had done." They'd get disciplined in some fashion. Then they'd all move on.

During the immediate aftermath of his beating at the hands of fellow officers, Mike Cox's first instincts were true-blue. The severity of the thrashing notwithstanding, Mike got that it had been a terrible mistake. His family was angry, but he couldn't see making a federal case out of it. Friends from the department's gang unit came by the house the first week to check on him. He wasn't up for talking much, but he listened. He heard gossip that the brass was giving those responsible some time -- a grace period of sorts -- to come forward before any kind of intense internal probe was begun. The tidbits gave Mike the idea this was going to get settled in a way he preferred both personally and as part of the fraternity himself -- quietly and within the organization. "I felt this loyalty to police in general," he said. He was optimistic, knowing full well police officers tended to protect another suspected of misconduct. But he also believed this went beyond any unspoken code of silence. When the victim was one of your own, it was a different ballgame.

Mike was confounded. The stories were like a punch in the stomach. Officials were saying his injuries were serious but they didn't know how he got hurt.

Then a story about him in the Globe only added to his anxiety. The story reported police officials were "trying to determine how plainclothes officer Michael Cox was injured in the line of duty last week." But comments by the spokesman were misleading, if not outright false. "We're not sure -- and he's not sure -- how he was injured."

"No official complaint?" thought Mike. The notion that police investigated violent assaults only after the victim filed a formal complaint was flat-out absurd. The department was making it sound as if the ball was in his court -- to both pursue the case and solve it.

The story itself presented another puzzle for Mike. In it, police sources were quoted as saying they were trying to sort out what had happened. One police source said, "We have no official complaint yet. Michael has not come in and said he was beaten up."

The caller, Mike decided, was not random, a nobody -- he was a cop who'd read the news story. He would never be able to prove it, but he knew it in his bones. Mike felt panic. He knew the call was a warning: Keep your mouth shut.

Mike found himself thinking about the crank calls. They were clearly connected to the story. He might be reading the story for the first time at midmorning, but Mike knew that cops working the overnight shift often grabbed the city's two morning newspapers.

Mike read on: "Officer Michael Cox, 29, a member of the Anti-Gang Violence Unit, suffered kidney damage and head wounds in the Jan. 25 incident, which occurred as police pursued four suspects for a shooting at a Roxbury eatery, sources said."

Later in the morning, a friend of Mike's called to tell him about the newspaper coverage. The story, a mere 289 words long, ran on Page 16 and carried the headline "Alleged Beating of Undercover Cop Probed." It reported that the department was looking into the possibility that "an undercover police officer was beaten by other officers at the height of a chase following a shooting last week." It was the first public disclosure that Mike had been a casualty in what so far had been heralded in the media as a night of sterling police work. Would the truth now begin to come out about what had actually happened at the fence on the dead end in Mattapan where the chase concluded?

The line went dead, and that was it. The calls ended. Mike and Kimberly weren't going to puzzle too much over it, not with all they had going on in the family, given Mike's condition.

He'd taken to sleeping on the living room couch after finding a tire slashed one morning when he left the house for work. Over the next few weeks the other three tires were cut up. His car was clearly targeted; it was the only one on the street that was hit. Mike was certain cops were the culprits, cops who'd adopted yet another technique to communicate what they thought of him, "that I was becoming some type, you know, of rat." In the police world, tire slashing was known to be one way cops expressed displeasure with one another.

One September night eight months after the beating, Mike jerked upright and leaned over the back of the couch. He thought he'd heard something outside. But his street was quiet. His unmarked police cruiser sat in front of his house, untouched.

Several nights after the meeting with Roach, the calls started again. "Virtually every night," Mike said. Sometimes the caller didn't say a word; other times he screamed or swore. Mike became convinced the caller was a cop using a kind of blunt force -- the linguistic equivalent of a nightstick or flashlight -- to keep him down and silent. But if that was the intent, the harassing calls had the opposite effect.

But, for Mike, this was good. He had privately begun to question the low-key nature of the department's response. Maybe his family was on the right track. Maybe the "grace period" was not so much time to allow the wrongdoers to step up as to enable a coverup to take root.

Roach showed up at the Coxes' in early February. "I just wanted him to leave as fast as possible," Mike said. He had met with Roach mainly to placate his family, but the meeting did last long enough for Mike to realize Roach was an outsider. "He knew nothing about the Boston police," Mike said. "He had not worked for them, and he didn't seem to be part of that culture."

When the stories about Mike ran in the Herald and Globe, Mike's family jumped all over them. They saw the stories as clear-cut evidence the Police Department was in coverup mode. They said, We told you so, Mike. You have to do something. Mike agreed to meet with an attorney one of his sisters had found. His name was Stephen Roach, a 45-year-old civil trial attorney. Roach had just started his own firm downtown. He had been practicing law for just over a decade, competently but without fanfare.

No assumption of wrongdoing? Mike couldn't get past that line. It was nine days since he'd been beaten, and everybody knew he'd been beaten -- mistakenly, perhaps, but he was beaten, and the beating was overkill, a case study of excessive force. But officials telling the public, "There is no assumption of any wrongdoing" did not sound like a department determined to get to the bottom of the beating of one cop by other cops.

The harassment accelerated as officers began receiving subpoenas in late summer to appear before a Suffolk County investigative grand jury. Mike had gone back to work in July, and his return wasn't going well. "I'd just walk into a room and, you know, people look at you like you're dirt." Some commanders reassured him his beating was unacceptable, but the talk was empty, particularly when he could see actual suspects still on the job. No one had yet been disciplined, despite the lies the investigation had already established. Instead, the crank calls continued, albeit with breaks. Once a crew of Boston firetrucks arrived in the middle of the night, apparently summoned by a false report that the Cox house was ablaze.

Now there were the tires. When Mike lay back down on the couch, a video camera, pointed out of the living room window, continued making its slow, whirring sound. The camera was aimed straight at Mike's cruiser. The car's shadowy image was displayed on a monitor attached by cables to the camera.

Boston police anti-corruption investigators had installed the camera. It was a primitive setup, requiring Mike to "do a lot of rewinding and setting up of this equipment, turning it on and off." Kimberly was put off by the whole thing. To her, the clunky equipment was a token, even patronizing response: "I didn't think that was a serious attempt for them to find out who was doing this." In fact, it became a symbol for how the couple viewed the overall investigation -- halfhearted, bungled, and wanting.

By early fall, Mike had seen enough. He'd always believed in the system, but he now felt it had fallen short. "I was failed by the Police Department," he said. Mike decided he was on his own in the search for justice. "I had to do something," he said, "regardless of what the DA's office or the Police Department was going to do." The continual harassment, rather than a deterrent, had become a prod. "I decided, along with my family, that I needed to find out, you know, who was involved, who did this."

Mike hired Steve Roach, and in late fall, he sued. He sued his fellow cops, his Police Department, and his city. He said his civil rights were violated when Boston police officers repeatedly beat and kicked him until he blacked out. He took on the police culture of silence and said his assailants joined others in a coverup.

Mike was in metamorphosis -- moving from cooperating victim in others' investigations to aggressor in the quest to hold his assailants accountable. He'd been a punching bag that night at the fence, and he'd felt like one ever since.

"It was humiliating what happened to me," he said. "There's no reason to treat anyone like that. And then to just leave them. And if they do it to me -- another police officer -- would they do it to another person if they got away with it?

On December 31, 1995, an estimated 1 million revelers turned out for Boston's First Night activities. For the occasion, more than 200 Boston police officers and 91 police cadets were deployed to keep the city's record of a festive and peaceful New Year's Eve intact. "We're going to keep this a safe and enjoyable way for people to celebrate," Mayor Tom Menino promised beforehand.

Mike Cox was not feeling particularly celebratory. His lawsuit against his police colleagues and his department could cost them their jobs, monetary damages, and "it could send them to jail." Mike now wrestled with a new fear: He'd become a troublemaker, and the quickest way for those troubles to end was "by me not being on this earth." That was the way Mike Cox's year ended -- believing his life was at risk. He'd been a cop for six years and knew the score. He understood his lawsuit meant he was locked in combat against the police culture, and, by taking it on, he had become the enemy. ª

This excerpt is from the new book The Fence: A Police Cover-Up Along Boston's Racial Divide, by Dick Lehr. Available this month from HarperCollins Publishers. Copyright©2009 by Dick Lehr. Now a journalism professor at Boston University, Dick Lehr was a Boston Globe reporter for nearly two decades. Send comments to magazine@globe.com.

© Copyright 2009 Globe Newspaper Company.