Mr. Acree said he was grateful for the new police tactics. “Any type of preventive measure from the police — you’ve got to be willing to do it,” he said. “These are real lives we’re talking about.”
Among those lives affected over the weekend: A 15-year-old was shot in the back around 6:30 p.m. on Sunday on the city’s West Side when a gray sedan drove up and someone inside started firing. A 20-year-old who had severe vision problems was shot in the head and killed after playing basketball at his favorite South Side park. And in the hours before dawn on Monday, two men riding along an expressway here were shot and wounded by gunfire from another vehicle — a pattern the police have seen rise in recent years along some of the city’s busiest thoroughfares.
On Tuesday, Chicago Police officials said that while no level of violence was acceptable, they were pleased that shootings had declined. “I think we’re trending down over all,” Kevin Navarro, the first deputy superintendent, said.
Beyond a single holiday weekend, some officials say they see modest signs of improvement in recent weeks. As of Tuesday, the city had seen 235 homicides in 2017, about a 4 percent decrease from the same period a year ago. The number of shootings in Chicago has dropped by more than 14 percent, though that remains well above the counts in the nation’s two larger cities, Los Angeles and New York.
A decline in shootings is especially pronounced, officials say, in two of the city’s most violence-prone districts, where special police centers were recently created as a way to use more predictive analytics, gunfire data and surveillance footage in real time to decide where to deploy officers. In one of those police districts — an area on the city’s West Side with the largest concentration of shootings over the Memorial Day weekend in 2016 – no shootings were reported this holiday weekend.
On Tuesday, the police announced the opening of a third special center inside a South Side police station, revealing giant computer screens that map 911 calls, squad cars and predictions of where homicides are most likely to take place soon. Three more centers are due to open this summer.
Yet many here said it was far too early to declare the city’s crisis of violence controlled. While somewhat lower than last year, the number of shootings over the weekend was still high. Shooting statistics can rise and fall abruptly, and some people wondered whether the city could afford to maintain higher police staffing levels beyond a long holiday weekend. Some praised the extra officers and the raids, but also questioned whether such tactics would worsen Chicago’s long-strained relations between the Police Department and the community, particularly in mostly black and Latino neighborhoods.
“I’m a little torn,” said William Calloway, a community activist. “We have to find a way for them to be present but not excessive. You don’t want it to feel like police are now occupying forces in neighborhoods.”
For those who lost loved ones over the weekend, no statistical trend really mattered. Jervon Morris, 20, was playing basketball in a South Side park not far from his house late Monday afternoon when shots rang out — again and again.
Mr. Morris, an avid basketball player who liked to draw N.B.A. logos despite being visually impaired, was struck in the head and killed. He had volunteered in that park since high school, and appeared to get caught in crossfire, said Rashawnda Rice, his sister. “I don’t think he even knew how to make an enemy,” said Ms. Rice, who said she had heard the shots from inside their house and hoped they were firecrackers. “I guess his first instinct wasn’t to get down on the ground, but to try to run home.”As is almost always the case in Chicago, nearly all the shootings took place on the South or West Sides, not the city’s wealthier and whiter downtown and North Side. Most of those shot were men, many of them in their 20s. Several of the shootings, including a suspected murder-suicide, were domestic disputes, the police said, rather than the sort of shootings that have plagued Chicago: gang shootings over disputes — and over previous gang shootings.
“Let’s not throw a parade yet,” said the Rev. Michael Pfleger, a Roman Catholic priest who leads a South Side parish. “To say we’re better than last year is good, but last year was disastrous, so it’s not a great benchmark. This is one weekend.”
Father Pfleger and others said that policing alone would not stop the city’s violence. Community leaders here called for more jobs in struggling neighborhoods, improved public education from a system that has wrestled with funding woes, and more low-income housing options in neighborhoods all around the city, not just in struggling ones.
“Is this a turnaround?” Father Pfleger said of the weekend shooting numbers. “I would be a little leery to say yet that this is a turning point. The turning point will be when we decide as a city that there won’t be two Chicagos.”