Nearly every police officer patrolling the streets of downtown and north Minneapolis will be outfitted with a body camera by the end of this week, in what department and city officials called a critical step in capturing crucial evidence while repairing fractured relationships between police departments and the communities they serve.

The estimated 100 officers in the downtown First Precinct started wearing cameras on July 11, officials said at an afternoon news conference at precinct headquarters.

By the end of the week, their counterparts in the Fourth Precinct, which covers most of north Minneapolis, will also have them. The rest of the city's officers will have them by mid-October.

"This is an important moment in the history of Minneapolis," Mayor Betsy Hodges said.

Minneapolis Police Chief Janeé Harteau said the cameras have already proven their worth in aiding the prosecution of suspects in several robbery and gun felony cases.

In one recent robbery, officers recorded the arrest of a suspect who was still carrying the hat and shoes he had reportedly stolen from someone earlier in the day. "The evidence was right there, captured on the body cameras" and turned over to prosecutors for charging, Harteau said.

By mid-October, all Minneapolis patrol officers will be equipped with body cameras.

Recent high-profile shootings in Falcon Heights, Dallas and Baton Rouge, La., have only intensified calls for all officers to wear the cameras, although police officials and reformers agree that they are not a panacea.

Hodges cited a study done in Orlando, Fla., that showed that officers who wore the cameras were less likely to use force and were the subject of fewer citizen complaints. Still, research on the devices' effectiveness nationally is mixed.

Law enforcement officials in Minneapolis and beyond see the cameras as a powerful evidence-gathering tool, which will shed some light on contentious police-public interactions, while reform advocates hope they will put officers on their best behavior.

587 cameras on streets

A total of 587 Taser Axon Body 2 cameras will be deployed in all five precincts by this fall, with officers in the Third Precinct expected to start carrying them next month, officials said. Officers in specialized units, such as K-9, mounted patrol, school resource officers and community response teams, will be required to wear the cameras, but detectives and those working undercover will not.

The department bought 41 extra cameras to replace those that malfunction and for spare parts, said Lt. Gregory Reinhardt, who heads the Business Technology Unit.

The playing card-sized cameras attach to the front of an officer's uniform and have a 140- to 150-degree field of view, which Reinhardt said lets the officer record interactions with the public.

Still, Reinhardt said, the cameras won't capture everything.

When confronting certain incidents, he said, officers will rely on their instincts, which won't show up on video.

He added that although the cameras can film in high-definition the system will not use facial-recognition software, as some privacy advocates have feared.

At the end of every shift, the footage will be uploaded to a cloud-based storage system, "so, if an asteroid crashes into the storage site, it's backed up somewhere else," he said.

In a provision that has drawn criticism, officers will in most cases be allowed to review the recordings before filing their reports. Officials point out that this is common practice in many other departments around the country.

The rollout of the devices, intended to improve transparency and accountability, encountered several delays as officials worked through last-minute technical problems.

The department earlier this month unveiled guidelines that would require officers to record most interactions with the public in their entirety, but insisted that it would continuously evaluate its policy on the cameras' use.

Officers will be required to switch on their cameras "any time an officer feels there might be a potentially adversarial interaction" with a citizen, said Deputy Chief Travis Glampe.

Glampe, who oversaw the cameras' rollout, said the feedback he has received so far has been mostly positive, although some officers complained that the devices tend to become dislodged during physical altercations.

In the meantime, he said, the department will continue tinkering with its camera policy, including deciding whether the devices will be used in SWAT team operations.

"The only time a policy is final is when we take it and throw it away," Glampe said.

Libor Jany • 612-673-4064 Twitter:@StribJany