It was the last thing I expected on a Tuesday night, walking out of a supermarket in Lincoln Park with six plastic bags in my hands. But then, when do you ever expect to be mugged? It was Sept. 22, 1999, at 12:20 a.m. First there was the sickening, dizzying fear as a stranger demanded my money, grabbed my shirt and tossed me to the ground. Then there was the surreal joy of realizing that God was watching out for me in his own bizarre way, as my skull bounced off the milk carton that had hit the pavement behind me. The almost giddy rush that came with the knowledge that if this punk had had a gun, he'd have pulled it on me by now. And the inner wisdom that if I could just fight the marauder off for 10, 20, 30 more seconds, someone would have to see me and save me.

After all, I was at a normally busy intersection. I was 100 feet from a bustling "L" station. And there were lights everywhere from the street lamps. I knew my mugger had to be crazy, but he was still on top of me, ripping through my pockets even as I absurdly screamed like a kindergartner fighting off a bully: "I only have a dollar! I only have a dollar!"

Even more absurdly, I flailed at him with my groceries, whacking him in the back with my orange juice carton and slapping him upside the head with my lettuce as tomatoes rolled onto the pavement around me. Finally, I recognize the sounds and sight of my salvation.

First, the screeching tires and brightened headlights of a sport-utility vehicle. Then, the sound of a door thrust open and a man screaming, "Get off him! I'm a cop and I've got a gun!" All I could see were the bright headlights, with no emergency lights or sirens to assure me that this was a patrol car. For all I knew, this was a Charles Bronson for the millennium about to execute his own real-life version of "Death Wish."

But at least my attacker was off me. He sprang up in terror and started to run. Then I heard the quick thud of his body hitting the ground and I leaped to my feet, grocery bags still in hand. My attacker was down, a knee in his neck and a shiny silver gun pointed at his temple. The man who was on top of him was, in his own words, offered later, "a 5 1/2-foot-tall Puerto Rican," wearing shorts and a straw hat straight out of Huckleberry Finn.

"Get this hat off my head and call 911!" he screamed, and I was too stunned to do anything else. I called in the police cavalry, a fleet of squad cars arrived and my mugger was taken into custody.

The man who had rescued me was, indeed, an off-duty police officer. His name is Andres Zayas and, as I later came to realize, he may have saved my life.

The very fact that I owed a police officer gratitude was even more surprising to me. I had established myself as a reporter for Chicago's alternative weeklies. I had written exposes on Chicago police brutality and Illinois state prison abuses. I had also been raised with a healthy skepticism of official authority and a wariness of police power by my father, who had spent his first 31 years suffering under the Communist police state in Poland.

Most specifically, I was a 28-year-old guy who had spent several Saturdays over the years attending traffic school because of my spotty driving record. Stir those factors together and you've got a recipe for disdain for the police.

Now I was forced to come to terms with my conflicting feelings about police. Because for the next four hours, until 5 a.m., we talked inside the sheltered confines of the 18th District police station on Chicago Avenue. Zayas made sure I was calm and collected about my brush with danger, but once assured, he laughed as he described the incident to other officers.

"You shoulda seen this guy! He looked like a lobster about to get dropped in a pot of boiling water!" Zayas laughed with the enthusiasm of a buddy in 7th grade. He commented on the fact that I never dropped my groceries, no matter how tense the moment. He had me recount the funny parts of my story to other officers as they arrived for their shifts.

By the time I was set free to go home, I realized we might become friends. Zayas had given me his police business card and written his cell phone and pager numbers on it.

"Call me if you need to talk," he said while shaking my hand goodbye. I wanted to talk, all right--to figure out what had compelled me to be so skeptical of the police, and to learn what compelled Zayas to become a police officer. We talked a few times by phone, but it wasn't until nearly five months later that we finally met up for a ride-along as he covered his shift in his assigned district, the 19th.

"Some might say making that arrest off-duty was a chance. I guess it was a chance, but I heard you screaming for help," said Zayas, as we rolled through the neighborhood streets and alleyways along his North Side patrol route. "What am I gonna do? Forget the fact that I'm a police officer? As a human being I can't stand back and ignore that."

Zayas, 34, speaks with a calm assurance that still falls far short of cockiness. It is the voice of an older brother offering wisdom to his younger sibling, of a man imparting life lessons to his children--which is fitting because he is a divorced father of two young sons. He recounts tales of officers who were injured or killed in other off-duty emergencies, but still feels assured that his training and his gun will provide him the upper hand he needs. He says the one thing that can shatter his confidence in the line of duty is finding children who have been harmed or are in danger.

He also informs me that my attacker had been out on parole for armed robbery. He tells me that my attack may have been humorous in some of the details, but was deadly serious in its intent. He tells me that I was the first person my attacker had been caught with when he didn't have a gun. It gives me a long, silent moment of pause.

Andres Zayas was born in Ft. Benning, Ga., the son of a machinist and Vietnam veteran father and a banker mother who moved to Chicago when he was just a few months old. He grew up seeing police officers as heroes, men and women who stepped in where others feared to tread in a quest to do good for society.

"As I grew older, I wanted to know what lay beyond the `Police Line Do Not Cross' tape that separated the cops from the public," he recalled. "But more importantly, I took a constitutional oath to defend my country in the Navy first, and then I took a state oath to defend the citizens of this city. I believe in that wholeheartedly, even if that makes me a die-hard romantic. There are a lot of policemen who are like that."