UnitedHealth’s Minnesota headquarters was rocked by two major protests just months before CEO Brian Thompson’s execution in Manhattan on Wednesday – as the boss’s former security contractor expressed dismay that he had no protection in the Big Apple.

Slain UnitedHealthcare CEO Brian Thompson, 50, was stationed at the company’s headquarters in Minnetonka, Minnesota, where more than 100 demonstrators gathered in April and July to protest an alleged “epidemic” of claims denials, Wall Street reports Journal.

During the July protests, 11 protesters were arrested, including people from Minnesota, Illinois, Maine, Texas, West Virginia and New York, according to Minnetonka police.

The People’s Action Institute, which led protests in April and July, said it was shocked by Thompson’s death – but still used the tragedy to highlight the alleged “crisis of denial” in America.

“We know there is a gun violence crisis in America. “There is also a crisis of denial of health care by private health insurance companies, including UnitedHealth,” the group said in a statement on Wednesday.

“The People’s Action Care Over Cost campaign offers people a productive, non-violent and democratic way to make change on this issue. Both crises must end. Our political leaders must take both into account,” they added.

Meanwhile, the NYPD is investigating engravings — which appear to contain the words “deny,” “depose” and “defend” — that sources say were found on live bullet and bullet casings left behind by the masked assassin after he shot Thompson .

The words are eerily similar to a 2010 book condemning the insurance business called “Delay, Deny, Defend: Why Insurance Companies Won’t Pay Claims and What You Can Do About It.”

UnitedHealth Group is the country’s largest private insurer and has a long and controversial history of denying customers’ claims.

The company, ranked fourth on the Fortune 500 list, is also currently facing an antitrust investigation by the U.S. Department of Justice.

Given the importance of UnitedHealth and Thompson’s position as insurance chief, Philip Klein – whose security firm has provided bodyguards to Thompson in the past – said he was surprised to learn the CEO was alone on Wednesday.

“It was normal for this company to have its own private security team looking after its company executives,” Klein told the WSJ.

UnitedHealth did not immediately respond to The Post’s request for comment.

Thompson was on his way to the Hilton hotel Wednesday morning to prepare for an investor conference when a gunman crept up behind him and fired several shots.

Thompson was hit in the back and right calf when he stumbled and collapsed in the middle of the sidewalk.

The shooter fled into an alley, then hopped on an e-bike and disappeared into Central Park while police continued to search for him.

The NYPD said the shooting was clearly planned and denied it was a random act of violence.

Thompson’s wife, Paulette “Pauley” Thompson, 51, said the family received threats before her husband’s killing.

“There had been some threats,” she told NBC News. “Basically, I don’t know, a lack of coverage? I don’t know the details. All I know is that he said there were some people who threatened him.”

A source confirmed to The Post that UnitedHealthcare informed investigators that Thompson had been the victim of threats — although the source noted that this was not unusual for someone in his position at a healthcare company.

A manhunt for the suspect is underway and the NYPD and Crime Stoppers are offering a $10,000 reward for information.