ST. PAUL — A growing number of Minnesota law enforcement agencies have partnered with front door camera maker Ring in an arrangement that allows them to request home security footage for use in investigations.

At last count, 13 local police and county sheriff’s departments in Minnesota had joined forces with the company. More than 400 nationwide have done the same since the program launched in 2018.

These partnerships offer the police a new way to interact with their communities. But for some, they raise questions about privacy.

"We’re in a highly technological era," Lt. Andy Galles of the Crow Wing County Sheriff's Office said. "Criminals advance, we need to advance along with them."

Founded in 2013, Ring is known for its line of motion-activated, smartphone-compatible home security cameras, which both resemble and function as doorbells. The company was acquired by e-commerce giant Amazon in 2018.

Police that work with the company have only limited access to video recordings that Ring devices capture. According to its website, police cannot remotely activate a user's camera and monitor what it sees.

Partnering agencies can only ask for footage from device users who live in a part of their jurisdictions where crime is being investigated. Footage requests are made through a software application that does not allow the police to target specific users.

Each request includes a description of the incident under investigation and a corresponding case number, and can only ask for video captured between a specific span of time. Ring owners who accept the requests can choose which recordings to share with the police.

Those who deny it can choose to indefinitely opt out of future requests. The company said that it does not provide the police with personal information on its customers unless they agree to a request, in which case it shares only their street and email addresses.

Minnesota police officials said the partnerships provide them with access to new public safety tools. Others worry that they represent another step toward mass surveillance.

University of Minnesota Law School professor JaneAnne Murray, who specializes in criminal law, said in an interview that the technology could potentially be misused to spy on ordinary people.

"That capacity to aggregate individuals' movements is something that should give us pause and certainly would give the Supreme Court pause," Murray said.

Detective Mike Passig admits that some Plymouth, Minn. residents had reservations about the city police department's arrangement with Ring when it became official in August. The department was the first in Minnesota to partner with the company.

"People were thinking we had access to their cameras," he said.

But since then, he said, the Plymouth police have made only made eight requests for footage. More handy, he said, has been Ring's companion social media app Neighbors.

The self-described "new neighborhood watch," Neighbors is open to anyone regardless of whether they own a Ring device. Users appear as anonymous to police departments that use the app.

Galles said the Crow Wing County Sheriff's Office has found the social media app to be valuable as well. Like Facebook and Twitter, he said, it can be used to easily disseminate public safety information.

Since partnering with Ring in October, Galles said, the sheriff's office has requested Ring footage only a handful of times. None of the requests produced anything of use to investigators, he said.

Ring has said that it cannot force the police to destroy videos shared with them because of public records laws. Joel Bonstrom, a crime analyst with the city police in Edina, Minn., said that officials with access to Ring footage have to treat it "the same as any other evidence."

Edina partnered with Ring beginning December, Bonstrom said, and police there have requested footage only twice since then. Two more Minnesota police departments joined up with the company in January.

In many cases, police departments elect to approach Ring about potential partnerships on their own. In Edina, Bonstrom said, Ring came to the police first.

Through a spokesperson, Ring declined to say how it chooses which departments to approach. In either case, Ring users receive phone notifications when their local police join Neighbors.

Police officials stressed that Ring and the Neighbors app will not substitute traditional police work but supplement it. Passig said that he doubts technology will ever progress to a point where it replaces the need for in-person responses, which he said help to develop trust.

"You’re never going to be able to replace the personal relationships that you form," he said.