Legislation that would limit law enforcement's use of drones has bipartisan support this year at the state Capitol.

Bills in the House and the Senate would require investigators to get a search warrant before they use a drone to monitor someone.

"The warrant requirement ensures that you've got to have a good reason to watch a person or a group of people," said Rep. John Lesch, DFL-St. Paul, who authored the House version of the bill.

"We're trying to limit the investigation of innocent people with technology where it's not necessarily warranted," he said. "I think it's Americans' appreciation of our privacy rights that is really paramount and [that's] why we're pushing the legislation."

The bill includes exceptions to that rule, in cases of emergencies, such as searches for a missing person, natural disasters or terrorism-related incidents.

Lesch has unsuccessfully proposed some version of this legislation several times since 2011. He found 18 other states that restrict law enforcement's use of drones.

University of North Dakota professor Joe Vacek has been tracking drone laws for 10 years. He sees growing support for requiring search warrants to gather information using a drone.

"All law enforcement officials that I've spoken with don't object to state statutes that require it," Vacek said. "It's just one extra step that they need to do. There may be some administrative requirements, but I haven't heard from anybody that I've spoken to [who's] saying, 'Well, this is going to be a huge hindrance in the way we enforce the law.'"

The Minnesota Sheriffs' Association did not respond to a request for comment on the legislation.

Many law enforcement agencies are still learning how to use drones, said Vacek, but he expects the use to expand.

Lesch thinks it's critical to have laws in place before technology such as facial recognition is added to drones' capability.

"Facial recognition technology was utterly useless except in very specific circumstances 10 years ago," he said. "That has changed drastically in the last 10 years, so because we don't know how they could be used in five years, we have an obligation to get ahead of that now."

Researchers are also testing algorithms they claim can identify "violent behavior" in crowds of people by analyzing drone video.

Lesch also wants to make data gathered by drones private, or he believes the data could be used to exploit innocent people caught in drone surveillance. He also wants agencies to delete drone data within 24 hours of gathering it.

Vacek said he was surprised by the bill's data deletion provision. He said most laws allow investigators to keep drone data for weeks — or even months.

Lesch's bill would also ban the use of weapons on drones, something Vacek said is already addressed in federal regulation.

Lesch said he thinks Minnesota failed to adequately regulate technology that monitors cellphones or automatically reads license plates until the technology caused privacy problems. He said he thinks there's still time to prevent abuse of drone technology.

"Policy measures are really important. It really doesn't matter if it's drones or facial recognition or whatever kind of technology," he said. "It's important we have policies in place on it before it gets deployed — not when we realize we made a bunch of really bad mistakes that change the lives of innocent people."

The bill will have its first hearing Wednesday at a meeting of the House Judiciary Finance and Civil Law Division.