Long before the shooting, before the manhunt and before the arrest of Luigi Mangione in connection with the killing of a health care executive, the Mangione name was well-known around Baltimore.

The Mangiones, fueled by the competitive, combative spirit of their immigrant patriarch, built a formidable family business that made them a force in local politics and charity.

When Nick Mangione Sr., Luigi’s paternal grandfather, thought that he was being discriminated against at country clubs in the early 1970s because he was Italian, he bought his own golf resort. When he got tired of waiting for permission to build a second golf course at one of his clubs, he sent in bulldozers to begin clearing the land. And when one of his sons was cut from a local soccer team, Mr. Mangione barred the team’s coach from his country club.

“Nick Mangione is foremost identified as a family man,” Thomas J. D’Alesandro III, the former Baltimore mayor and late brother of former Speaker Nancy Pelosi, told The Baltimore Sun in 1995. “He is maybe a little rough around the edges and maybe with an aggressive personality, but a man with a big heart.”

When he died in 2008, the elder Mr. Mangione left behind 10 children, more than 35 grandchildren and a collection of business holdings, which now include two country clubs, a chain of nursing homes and a local conservative radio station. The Mangiones are longtime supporters of numerous local causes and institutions, including Loyola University Maryland and the Greater Baltimore Medical Center, where the high-risk obstetrics unit bears the Mangione name.

Until this week, those commercial and philanthropic pursuits were the principal sources of the family’s prominence. Then, on Monday, Luigi, 26, was arrested in Altoona, Pa., and charged with second-degree murder and other offenses in connection with the killing last week of Brian Thompson, the chief executive of UnitedHealthcare.

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