“I don’t think there’s a sense that there’s something wrong in the department,” said Ed Zuercher, the city manager. “The issue is, ‘What’s going on in our community in total that assaults on police officers are up, the use of weapons against police officers is up, and that police officer-involved shootings are up?’”

Critics say the Police Department cannot — or will not — substantiate such assertions. The department “makes these really biased claims against the community, and when we push back asking for the stats, they refuse to release the cases they say they’re citing,” said Viridiana Hernandez, executive director of Poder in Action, a Phoenix-based community group.

Since the early 1990s, Phoenix’s violent crime rate has declined along with the rest of the nation’s, despite ticking up in the past few years, and is on a par with that of other large cities.

Chief Jeri Williams has commissioned a study of the rise in shootings and increased officer training — though a spokeswoman did not respond to questions about what kind of training. Chief Williams said the shootings this year have had little in common with one another. “If you look at other cities across the country, they might be able to point to one geographical area, one group of people, one criminal element,” but not so in Phoenix, she said.

In Mr. Zepeda’s case, he says he was the victim. The Maricopa County Attorney’s Office declined to prosecute him, citing “no reasonable likelihood of conviction.”

“I can’t breathe!”