By Michael Wilson | July 22, 2011

The police officer, recalling that night, sounds like an actor in a fast-food commercial: “At some point, something told me, grab a Big Mac.” And so on a freezing January night in 2005, the officer, John Florio, then 39, stopped at the drive-through window of a McDonald’s in the Hunts Point section of the Bronx. He ordered the combo, a Big Mac with fries and a Coke.

“Have a nice night,” a young man in the cashier’s window said, according to Officer Florio.

“You, too,” the officer replied.

He drove away, with his dog, Dodger, a member of the Police Department’s canine unit, in the back seat. Officer Florio was heading toward Randalls Island to give Dodger a bathroom break and a run. As he drove, he bit into the burger. Top-row teeth met bottom-row teeth, and the course of two lives changed.

“I felt something hard and sharp on the left-hand side of my face,” he said on a witness stand five years later. Something had cracked: “My tooth.”

Inside the Big Mac were several shards of broken glass.

It is impossible to overstate the seriousness with which the police take any attempt to harm one of their own. To the passer-by that night, it must have looked as if an officer had been drawn and quartered in the McDonald’s: there were two inspectors, two captains, three sergeants and five detectives among other officers at 875 Garrison Avenue.

They combed the kitchen for glass and questioned employees and a manager, and they took the young man assembling sandwiches that night, Albert Garcia, then 18, into a back room, where he was questioned for about three hours. He confessed.

“I started to make the sandwich and I was about to finish it,” he wrote in a statement for detectives. “I put the little pieces of glass into the burger as a joke.” He wrote, “I didn’t know it was going to be sold to a cop.”

Then the case that seemed so open and shut just kept opening.

Five years passed before Mr. Garcia’s trial began in the Bronx, and by then he had not only renounced his confession, but his lawyer, Raymond J. Aab, had accused Officer Florio of planting the glass in his own burger to make a quick buck from McDonald’s.

The officer guessed that he bought the Big Mac around 11:30 that Saturday night, Jan. 29, 2005, but he had no receipt. He said Mr. Garcia had handed him the bag. He bit into the glass a couple of minutes later, he testified, but he did not call his sergeant until 12:07 a.m., after stopping at Randalls Island for his dog. He followed the sergeant’s command to get checked out at Long Island Jewish Medical Center, and he told doctors that he thought he had swallowed glass.

One doctor said, five months later, that he had had three foreign-objects-in-McDonald’s-food cases that week, all from different locations. Doctors found no sign of cuts to Officer Florio’s throat, and X-ray tests came back negative. But Officer Florio said he monitored his stool for several days after, going to the bathroom in a bucket and examining its contents, and he found five shards of glass that had apparently passed through him without causing injury.

Inside of two weeks, Officer Florio sued McDonald’s for $6 million. This would prove to be a tactical mistake, for the civil action allowed the defense team to question him and other police officers in depositions, a luxury unknown to most lawyers defending criminal cases. The depositions contradicted one another in various places, and a defense theory emerged: Officer Florio planted the glass and never laid eyes on Mr. Garcia that night; nor did Mr. Garcia see the officer. The cashier, a young woman, served him the burger.

But when detectives, believing Officer Florio’s story, interviewed Mr. Garcia and he appeared nervous, they pushed harder, and he confessed.

Officer Florio, the defense claimed, had learned of Mr. Garcia’s existence only many hours later, in a precinct station house, and, quite likely shocked that anyone had confessed to something that did not happen, said yes, that’s the guy.

The defense theory worked. A jury acquitted Mr. Garcia in March 2010.

Officer Florio, since retired, settled his lawsuit against the owners of that Bronx franchise restaurant for $15,000, his lawyer, Richard M. Kenny, said. It was a fraction of what he had sought.

Officer Florio declined to comment, but Mr. Kenny said: “I’ve kicked a lot of people out of my office who I believe are trying to perpetrate fraud. This guy is as legitimate a guy as I’ve ever met.”

Mr. Garcia said that he had gone on, improbably, to work at a White Castle restaurant a few months after his arrest, and that his new employer did not know it had hired “Burger Boy,” as people in Hunts Point called him. He now works for Walgreens, has two children, and has a lawsuit pending against the city and Officer Florio. A scheduling conference in that case is set for next month.

“The reason I made a false confession is because I was scared,” he said this week. “I’ve never been in that type of position before. I gave up mentally. I was exhausted. I was hungry. I was thirsty. The only thing I was thinking about was going home.”

A police spokesman, Paul J. Browne, shrugged off Mr. Garcia’s lawsuit.

“It’s no surprise that the plaintiffs’ bar seeks remuneration for clients, regardless of how dubious their claims,” he said.

The Big Mac remains in evidence six years later, in a city freezer. The case of the broken glass is not even its only mystery. Investigators found a strand of hair in the burger box, but forensic tests showed that it belonged to neither the young man who was accused in the case nor the officer who paid for a meal and drove away.