For 400 days, Chicago withheld video of an officer fatally shooting 17-year-old Laquan McDonald until a Cook County judge ordered its release. Public support for police body-worn cameras has grown in the wake of several high-profile shooting deaths, including McDonald’s. But whether cameras will improve police accountability and transparency, as supporters expect, depends heavily on how and when they’re used and whether the footage is released.

These details are governed by state laws and local policies that are still very much up for debate.

“A lot hangs in those details,” said Nancy La Vigne, director of Urban Institute’s Justice Policy Center. “Those policies and practices can make the technology more or less powerful in its intended impact. And there’s a high degree of variation among states and localities.”

While the footage in McDonald’s case came from dashboard cameras and not body-worn cameras, questions about when—or whether—to release the videos touch on the same issues. Illinois state law says that police can withhold footage from public records requests to protect active investigations—what Chicago argued it was doing and had always done. But McDonald’s case has prompted the city to take another look at its video-release policy.

Chicago is not alone in grappling with the policies surrounding police cameras. Several cities are deploying body-worn cameras even as legislation governing their use is being written, which can lead to confusion when department policies bump up against state wiretapping and public records laws already on the books.

“In one Pennsylvania jurisdiction, the state statutes around eavesdropping were inhibiting their ability to use the cameras the way they had envisioned,” La Vigne said. “You can imagine law enforcement wondering how useful these cameras are if they need to ask permission to record. How does that apply if you’re in a high-speed chase?”

Several states have passed or are considering legislation specific to body-worn cameras, sometimes amending existing laws in an effort to balance privacy and transparency. And individual police departments—in some cases, without specific state laws to guide them—are developing their own policies for when to turn cameras on and off, how long to store footage, and when to release videos to the public.

“Right now, until a state policy comes into effect, every city or municipality has free rein on how they want to create their own policy,” said Kerry Condon, president of the Anaheim Police Association, who helped develop his city’s body-worn camera policy: “It’s one of the most important policies that I’ve dealt with in 25 years of law enforcement.”

When and where can body-worn cameras be used?

Nine states have passed legislation specifying when and where cameras can be used, while similar bills are pending in 16 states.

In Pennsylvania, the state’s wiretap law prevents police from recording inside a person’s home without permission. Pennsylvania is one of 37 states as of January 1 that restricts recordings where privacy is expected, but state legislators are seeking to amend that law for police officers. Some law enforcement officials are concerned that officers will be distracted if they have to turn the camera on and off during a chase or accidentally violate the law in the rush to respond.

Pittsburgh Police Lieutenant Ed Trapp, project manager of the department’s body-worn camera program, said that he sees the camera as a reporting tool—one that is even more critical in a person’s home to ensure accountability and transparency for the resident and the police officer.

“Going into a house is one of the most intrusive things government does,” Trapp said. “Why would that be the one time you’d want to turn the cameras off?”

Until the state law is changed, Pittsburgh police officers have been instructed to shut off their cameras as soon as they are dispatched to a private residence.

In Tennessee, lawmakers are considering bills that would require police to wear body-worn cameras “at all times when the officer is on duty” and record footage of “all the officer’s activities.” Other states’ laws are less prescriptive, so it’s up to department policies to clarify the issue.

Will the public get to see police camera footage?

Supporters of body-worn cameras may assume that the public will have access to the footage, but that’s not always the case. Nearly every state has exemptions to the public records laws for law enforcement, and those exemptions can stand in the way of realizing greater transparency through body-worn cameras.

“There are certain states whose public records laws are very broad and basically make all the video releasable, and we think that could be a real privacy problem,” said Jay Stanley, senior policy analyst at the ACLU. “But there are other states and departments where the police are trying to release nothing, and that is also not the right balance.”

Washington State’s strong open-government laws require public agencies to comply with public records requests, with only narrow exceptions. In response, the Seattle Police Department launched its own YouTube channel of body-camera videos in early 2015. But the redacted videos are so blurred out, it’s hard to make out what’s being filmed.

In Pittsburgh, the police department’s current policy is not to release any footage, Trapp said. The department is waiting to see if the legislature will address how public records requests apply to police body-camera videos.

How should states proceed?

While support for body-worn cameras is high, La Vigne cautions that deployment may be speeding ahead of policy development and evaluation. To help advance that conversation, the Urban Institute is identifying best practices for how officers tell people that they are being recorded and studying how differences in body-worn camera policies affect police use of force, citizen complaints, and police-community relations.

“It’s a challenging public policy balancing act,” La Vigne said. “On one hand, it’s important to safeguard the privacy of people captured on camera, including children, witnesses, and bystanders. On the other hand, the main purpose of body cameras is to enhance transparency. The good news is that state legislators are quickly refining the legal framework surrounding body-worn cameras, hopefully in a way that serves both interests.”