The officers who respond to 911 calls are now outfitted with body cameras in all five of the city’s precincts, Minneapolis Police Department Chief Janée Harteau announced Wednesday.

Harteau said nearly 550 body cameras have been assigned, and the department conducted 1,100 hours of training in 90 separate sessions for the officers who wear them. The citywide rollout of body cameras began in the downtown First Precinct in July and was completed at the end of October.

She said body cameras were “critical” to achieving transparency.

“It’s another set of eyes,” Harteau said. “It’s also important in accountability, both for the officers (and) also the people they come into contact with.”

Mayor Betsy Hodges described the body camera rollout as a “big success” for both the city and its police department.

“These are challenging times across the country for police departments and the communities they serve, particularly communities of color,” Hodges said. “While not the only tool, body cams are an important tool for improving police-community relationships.”

The body cameras were purchased from Taser International through a five-year, $4-million contract approved in February by the City Council. The city also received $600,000 from the U.S. Department of Justice to launch the program.

Thirty-six Minneapolis officers wore body cameras during a 2015 pilot project.

Harteau said the department already had amassed an archive of 55,000 videos shot by police body cameras totaling more than 6,500 hours. The average length of the videos was 7 minutes, she said.

Officer Justin Churchill, who joined Harteau and Hodges at the Nov. 2 event announcing the completion of the rollout, said, like many of the force’s veteran officers, he was “a little reluctant” to wear a body camera at first. But Churchill said he became more comfortable with the technology when he discovered how easy it was to use and how it could help with the gathering of evidence, especially on “high-stress calls.”

“Sometimes you miss an answer. Sometimes you miss a detail,” he said. “The great thing about these (body cameras) is we can go back and actually review that and see what details we missed. And then that way we can include it in our report, and it may be very beneficial to prosecution or towards someone’s innocence, so it can work a couple of different ways.”

The department’s body camera policy requires officers to activate the cameras in a variety of situations, as long as it’s safe to do so. Those situations include traffic stops, searches, “any contact that is, or becomes adversarial” and when they are advising a person of their Miranda rights.

Officers are encouraged but not required to inform members of the public when they are being recorded, unless asked.

Depending on what has been recorded, department policy mandates that the video is retained for up to seven years — or longer, in the case of a “significant” event, such as a felony or an incident of alleged police misconduct.

City Attorney Susan Segal said the cameras were expected to produce evidence that could be used to prosecute criminal cases more effectively.

“We in fact have already had our first domestic violence jury trial where we were able to present body cam video, so we were able to show the jury the victim — in real time, as officers responded to the call — describing her injuries and describing what happened,” Segal said.

Segal anticipated the cameras would be particularly useful in assault and drunken-driving cases, too.