The man suspected of fatally shooting a US politician and her husband, and wounding another and his wife, had “stalked his victims like prey” before opening fire at their homes while elaborately disguised as a law enforcement officer, prosecutors said on Monday.

Vance Boelter was allegedly wearing a “hyperrealistic” silicone face mask, a tactical vest and body armour when he arrived at the home of state Senator John Hoffman and his wife, Yvette Hoffman, in Champlin, Minnesota, early on Saturday, according to acting US attorney for the District of Minnesota Joseph Thompson.

Wielding a flashlight and a handgun, the 57-year-old allegedly knocked on the Hoffmans’ door around 2am and shouted: “This is the police! Open the door!”

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His black SUV had emergency lights and a license plate that read “police”, Thompson said.

The couple answered the door together, the prosecutor said at a news conference. He said Boelter shone his flashlight in their faces, said there had been a shooting reported in the house, and asked them if they had weapons.

When Boelter lowered his flashlight, the couple shouted that he was not a police officer, he said.

Boelter then allegedly announced “this is a robbery” and tried to force himself into their home.

Hoffman tried to push Boelter out of his home, but the suspect shot him and his wife repeatedly before fleeing to his next target’s home, Thompson said.

The Hoffmans’ daughter called 911. The couple were severely injured and remained hospitalised.

Meanwhile, Boelter continued on his alleged rampage, which he appeared to have plotted for “quite some time”, though it’s still unclear why, officials said.

Authorities said there were more than 45 names of state and federal elected officials in multiple notebooks found in the suspect’s SUV and home.

“Boelter planned his attack carefully,” Thompson said.

“He researched his victims and their families. He used the internet and other tools to find their addresses and names, the names of the family members. He conducted surveillance of their homes and took notes of the location of their homes.”

After allegedly shooting the Hoffmans, Boelter went to the homes of at least three other Minnesota state politicians with the intent to kill them, Thompson said. The next two were not home, and prosecutors declined to identify them Monday.

But Democratic state representative Melissa Hortman and her husband, Mark Hortman, were at their Brooklyn Park home when Boelter arrived around 3.30am, authorities said.

By that time, two local police officers were dispatched to conduct wellness checks on the homes of local officials, including the Hortmans.

The officers arrived at the Hortmans’ home just as Boelter was standing in front of it, officials said.

Boelter rushed into their home through the front door and repeatedly opened fire, killing the couple, Thompson said.

The suspect fled out the back door, dropping his mask and body armour on the way, Thompson said.

He called the alleged crimes “the stuff of nightmares”.

In a statement shared Monday evening on X — formerly known as Twitter — by Minneapolis TV journalist Caroline Cummings, the Hortmans’ adult children, Sophie and Colin Hortman, said they were safe, with loved ones and grateful for the support and privacy they’ve received.

“The best way to honor our parents’ memory is to do something, whether big or small, to make our community just a little better for someone else,” the statement said.

After the attacks, Boelter allegedly texted his family: “Dad went to war last night… I don’t wanna implicate anybody,” according to an affidavit.

In a message to his wife, Boelter apologised and appeared to warn her about an incoming police presence, the affidavit said.

“Words are not gonna explain how sorry I am for the situation,” the text read. “There’s gonna be some people coming to the house armed and trigger-happy and I don’t want you guys around.”

Police searched his wife’s car and recovered two guns, $10,000 in cash and passports for her two children, who were in the car at the time of the search, according to court records.

After a two-day manhunt, which was the state’s biggest, the suspect was found crawling in a field Sunday night, authorities said.

He cooperated with law enforcement officers and “gave up peacefully”, authorities said.

Boelter faces multiple federal charges, including two counts of stalking and two counts of murder.

The murder charges are punishable by life in prison or death, officials said. Thompson said it’s too soon to determine whether prosecutors will pursue the death penalty.

At his federal court hearing Monday afternoon, Boelter said he understood what he is being charged with.

Boelter told a judge he makes $540 a week through his part-time job and could not afford a lawyer.

A judge said he would appoint a federal defender and scheduled the next hearing for June 27.