Former House Speaker Melissa Hortman and her husband, Mark, were killed in their Brooklyn Park home early Saturday. Senator John Hoffman and his wife, Yvette, were injured at their Champlin home, about 15 kilometres away.

Authorities named 57-year-old Vance Boelter as a suspect, saying he wore a mask as he posed as a police officer, even allegedly altering a vehicle to make it look like a police car.

More than 24 hours after authorities first confronted him outside Hortman’s home, Boelter was still on the loose after fleeing on foot. The FBI issued a reward of up to US$50,000 (A$77,000) for information leading to his arrest and conviction. They circulated a photo taken Saturday of Boelter wearing a tan cowboy hat and asked the public to report sightings.

Investigators found a cowboy hat near the vehicle and were working to determine whether it belongs to Boelter. Law enforcement officers were searching the area, including nearby homes. The officials could not discuss details of the ongoing investigation and spoke to The Associated Press on condition of anonymity.

The search was happening in rural Sibley County, roughly 80 kilometres southwest of Minneapolis, where Boelter had a home with his wife and five children. Residents in the area received an emergency alert about the located vehicle that warned them to lock their doors and cars.

A crowd of officers were seen congregated on a dirt road near the abandoned dark sedan believed to have been used by Boelter. Doors on both sides of the car were splayed open, with discarded items scattered near the vehicle. Some officers broke off and walked into a wooded area off the road. The car was later towed away.

“We believe he’s somewhere in the vicinity and that they are going to find him,” US Senator Amy Klobuchar of Minnesota said Sunday on NBC’s “Meet the Press.” “But right now, everyone’s on edge here, because we know that this man will kill at a second.”

The shootings come as political leaders nationwide have been attacked, harassed and intimidated amid deep political divisions. Lawmakers said they were disturbed by the attacks as Twin Cities residents mourned.

Brightly coloured flowers and small American flags were placed Sunday on the gray marbled stone of the Minnesota State Capitol along with a photo of the Hortmans. People scrawled messages on small notes including, “You were our leader through the hardest of times. Rest in Power.”

Pam Stein came with flowers and kneeled by the memorial. An emotional Stein called Hortman an “absolute powerhouse” and “the real unsung hero of Minnesota government.”

“She had a way of bringing people to the table and getting things done like no one else could do,” said Stein, a retired lawyer.

The Hoffmans were recovering from surgery, according to their nephew, Mat Ollig.

Authorities have not yet given details on a motive.

A list of about 70 names was found in writings recovered from the fake police vehicle that was left at the crime scene, the officials said. The writings and list of names included prominent state and federal lawmakers and community leaders, along with abortion rights advocates and information about healthcare facilities, according to the officials.

A Minnesota official told the AP that lawmakers who had been outspoken in favour of abortion rights were on the list. The official spoke on the condition of anonymity because the investigation was ongoing.

The attacks prompted warnings to other state elected officials and the cancellation of planned “No Kings” demonstrations against President Donald Trump, though some went ahead anyway, including one that drew tens of thousands to the State Capitol in St. Paul. Authorities said the suspect had “No Kings” flyers in his car.

Law enforcement agents recovered several AK-style firearms from the suspect’s vehicle, and he was believed to still be armed with a pistol, a person familiar with the matter told AP. The person could not publicly discuss details of the investigation and spoke on condition of anonymity.

Boelter is a former political appointee who served on the same state workforce development board as Hoffman, records show, though it was not clear if or how well they knew each other.

Around 6 am Saturday, Boelter texted friends to apologise for his actions, though he didn’t say what he had done.

“I’m going to be gone for a while. May be dead shortly, so I just want to let you know I love you guys both and I wish it hadn’t gone this way. … I’m sorry for all the trouble this has caused,” he wrote in messages viewed by the AP.

Police first responded to reports of gunfire at the Hoffmans’ home shortly after 2 am Saturday and found the couple with multiple gunshot wounds.

Local police from Brooklyn Park were assisting with the call and decided to proactively check on Hortman’s home nearby, Brooklyn Park Police Chief Mark Bruley said Saturday.

There, they encountered what appeared to be a police vehicle and a man dressed as an officer leaving the house. Officers confronted him, he fired at them and officers returned fire. The suspect then retreated back into the home and fled on foot, Bruley said. He left behind the vehicle designed to look like a police car where authorities later found writings.

On social media, Gov. Tim Walz remembered Hortman Sunday as, “The most consequential Speaker in state history.”

Hortman, 55, had been the top Democratic leader in the state House since 2017. She led Democrats in a three-week walkout at the beginning of this year’s session in a power struggle with Republicans. Under a power-sharing agreement, she turned the gavel over to Republican Rep. Lisa Demuth and assumed the title speaker emerita.

Hortman used her position as speaker in 2023 to champion expanded protections for abortion rights, including legislation to solidify Minnesota’s status as a refuge for patients from restrictive states who travel to the state to seek abortions — and to protect providers who serve them.

The couple had two adult children.

Hoffman, 60, was first elected in 2012 and was chair of the Senate Human Services Committee, which oversees one of the biggest parts of the state budget. He and his wife have one adult daughter.