For 20 years, Brian Thompson, the health care executive killed in a shooting in Manhattan on Wednesday, climbed to the top of UnitedHealthcare.

The 50-year-old chief executive of the conglomerate UnitedHealth Group, the largest health insurer in the United States, was shot dead by a masked assailant in midtown Manhattan on Wednesday morning in what police are calling a “brazen, targeted attack.”

A graduate of the University of Iowa, Thompson joined the company in 2004 from accounting giant PricewaterhouseCoopers. He was named Chief Executive Officer of UnitedHealthcare in April 2021 after serving in several other roles, most recently as Chief Executive Officer of UnitedHealthcare’s Government Programs business.

UnitedHealth Group is the fourth largest publicly traded company in the United States after Walmart, Amazon and Apple.

Thompson, a father of two, lived in a suburb of Minneapolis, about a 20-minute drive from the company’s headquarters.

His wife, Paulette Thompson, told NBC News that her husband had received threats.

“There had been some threats,” she said. “I don’t know any details. All I know is that he said there were some people who threatened him.” She said police told her the shooting was “a planned attack.”

“He was a good person and I’m so sad,” Elena Reveiz, Thompson’s sister-in-law, told the New York Times.

Thompson, who led a department with about 140,000 employees, attended the company’s investor conference at the Hilton Hotel in midtown Manhattan. He was shot outside the hotel and later died in hospital. The police are still looking for his murderer.

“We are deeply saddened and shocked by the passing of our dear friend and colleague Brian Thompson, CEO of UnitedHealthcare,” the company said in a statement.

The company added: “Brian was a valued colleague and friend to everyone who worked with him. We are working closely with the NYPD and ask for your patience and understanding during this difficult time. Our thoughts are with Brian’s family and everyone who was close to him.”