At the height of the Baltimore Police Department's experiment with zero-tolerance policing in 2005, the number of people arrested reached six figures— a statistic that sparked protests and came to symbolize what critics called a misguided policy of mass arrests.

Prosecutors not only criticized the arrests for minor infractions such as loitering and drinking in public, they declined to file formal charges in about a third of the cases.

Now, a police commissioner armed with a strategy of more targeted enforcement of violent gun offenders has the department on track to record half as many arrests as five years ago — with the added benefit of crime going down.

Just as important, the number of cases tossed by prosecutors in the immediate aftermath of arrests has plunged to less than 8 percent this year.

For police, the numbers represent the first significant proof that a shift away from arresting people for petty crimes — under the guise of lowering crime by instilling fear — has worked, even if some people in neighborhoods feel the police are not tough enough.

"We've been working on this for the past four years, and we're finally starting to see it improved," police spokesman Anthony Guglielmi said.

Police Commissioner Frederick H. Bealefeld III has said he has reduced the number of arrests while also seeing the number of homicides drop to a 20-year low, and significant drops in other categories such as shootings.

Bealefeld declined interview requests for this article. But in 2007, the year he took over amid soaring crime rates, he called the number of arrests being made by officers in earlier years, "mind-boggling," and he asked, "Did we really accomplish a lot doing that?"

But some complain the pendulum has swung to the other extreme — police aren't doing enough to quell violence.

Israel Cason, executive director of the I Can't, We Can drug treatment program in Park Heights, said it is less common to see police "slamming people on the ground, emptying their pockets on the street."

"You don't see that too much no more," he said.

The downside, he said, is that drug dealers are congregating on street corners again without getting challenged.

"They know what [the drug dealers] are doing, but [the police] don't do nothing," Cason said. Referring to free samples of drugs that dealers circulate through the community, he said: "We got testers out here every day, the police stand right there with them. They went from one extreme to the other."

Ellsworth Johnson-Bey, who leads the Fraternal Order of Ex-Offenders, said police are still targeting people in high-crime areas, but he believes those interactions are less likely to result in an arrest and trip to Central Booking.

"They've got the hook," he said of police contact with suspected criminals. "But they can't get the fish," he said of them not making arrests.

The legal director of the Maryland chapter of the American Civil Liberties Union and a former assistant state's attorney who reviewed charges filed by city police attributed the drop in so-called "declined cases" to a philosophical shift by new leadership in the state's attorney's office.

"The police [department] didn't suddenly revolutionize itself," said Page Croyder, a former deputy state's attorney in Baltimore. "They have had Bealefeld in place for several years now, touting his new policies. It's the [state's attorney's office] administration that is new."

Elizabeth Embry, the deputy prosecutor under newly elected State's Attorney Gregg L. Bernstein, disputes that conclusion. She said the office more carefully reviews "quality-of-life crimes," along with defendants' criminal history and concerns from the community before summarily dismissing charges.

But Embry said prosecutors are not taking on a significantly larger number of nuisance crimes that would explain the new numbers. She said police this year have arrested 4,600 fewer people on misdemeanor drug and nuisance crimes, fueling the decline in both arrests and in dropped cases.

This year alone, the number of people arrested and then released without being charged stands at 1,200, down 78 percent compared with this time last year.