By Tom Polansek and Nathan Layne

MINNEAPOLIS (Reuters) -Police arrested a man on Sunday who allegedly shot dead a Democratic state lawmaker and her husband while posing as a police officer, according to ABC News, citing several sources.

ABC News said the man was arrested near his farm near Green Isle, Minnesota, but Minnesota Department of Public Safety did not immediately respond to a request for comment on the arrest.

A massive manhunt has been underway following the shooting deaths of Melissa Hortman, the top Democrat in the Minnesota House, and her husband, Mark, which Governor Tim Walz characterized as a "politically motivated assassination."

Authorities had said earlier that they had found a car, hat and other items belonging to the suspect shooter, Vance Luther Boelter, 57, in a rural area southwest of Minneapolis, but had not found him yet.

"We're certainly operating as though he's still alive, and believe he is at this time," Drew Evans, head of the Minnesota Bureau of Criminal Apprehension, told a news briefing before the ABC news report.

Boelter fled on foot early on Saturday when officers confronted him at Hortman's Brooklyn Park home.

Police say the same gunman that killed Hortman had earlier shot and wounded another Democratic lawmaker, state Senator John Hoffman, and his wife Yvette at their home a few miles away, authorities said.

Hoffman was undergoing surgery after being hit with nine bullets and "is closer every hour to being out of the woods," Yvette said in a text message posted to social media by U.S. Senator Amy Klobuchar, a Democrat.

"We are both incredibly lucky to be alive," Yvette said in the message.

Authorities in Sibley County, about an hour by car from the scene of the crime, instructed residents to keep their doors locked after finding the suspect's car.

The location of the car in Faxon Township is about four miles (6.4 km) east of Boelter's listed home address in Green Isle, which was searched by law enforcement officers on Saturday.

The gunman had left behind a different vehicle outside Hortman's house in suburban Minneapolis that resembled a police SUV, including flashing lights, and contained a target list of other politicians and institutions, officials said.

Boelter has links to evangelical ministries and claimed to be a security expert with experience in the Gaza Strip and Africa, according to online postings and public records reviewed by Reuters.

The Minnesota Star Tribune, citing law enforcement officials, reported the target list included abortion providers and several dozen Minnesota Democrats, including Walz, who was also the Democratic vice presidential candidate last year, and Klobuchar, a 2020 presidential candidate.

"There clearly was some through line with abortion, because of the groups that were on the list. So that was one of his motivations," Klobuchar said on NBC's "Meet the Press."

The killing was the latest in a series of high-profile episodes of U.S. political violence, including the attack on former Democratic U.S. House Speaker Nancy Pelosi's husband at their home in 2022, the attempted assassination of Donald Trump during last year's presidential campaign, and an arson attack at Pennsylvania Governor Josh Shapiro's house in April.

GUNMAN POSED AS OFFICER

Damon Voight, who lives down the road from Boelter's house in a rural area of Green Isle, said his wife was afraid with the suspect on the loose.

"My wife is freaked out," Voight said. "She's like, 'We've got guns in the house, right?'"

The city of Champlin, home to the Hoffmans, said it shut down its annual Father Hennepin festival for the weekend, which included live music and a carnival.

Outside the state capitol in St. Paul, a small memorial had taken shape, with flowers, American flags and handwritten messages on yellow post-it notes.

"Justice for Melissa," read one note, with a drawing of a heart on it.

Klobuchar said she had seen both Hortman and Hoffman at a political dinner on Friday, just hours before they were shot.

"We started out together in politics, moms with young kids, and somehow she was able to balance getting to know every door, knock on every house in her district, while raising two children - Girl Scout leader, she taught Sunday school," the U.S. senator said of Hortman, 55.

The attacks started around 2 a.m. (0700 GMT) on Saturday, when authorities said the gunman shot the Hoffmans in their home before driving several miles to Hortman's home in neighboring Brooklyn Park.

The FBI released photos of the suspect wearing a rubber mask and a police-like uniform.

(Reporting by Tom Polansek and Nathan Layne; Additional reporting by Michelle Nichols, Leah Douglas, Michael Martina, Costas Pitas and Katharine Jackson; Writing by Joseph Ax and Andy Sullivan; Editing by Michelle Nichols, Bill Berkrot, Diane Craft and Michael Perry)