Carl Vergari, who streamlined criminal justice in Westchester County during a record 25 years as district attorney, died Sunday in West Palm Beach, Fla., where he had retired. He was 84.

Vergari oversaw two of Westchester’s most sensational cases the conviction of schoolmistress Jean Harris in the 1980 shooting death of her lover, Scarsdale Diet developer Herman Tarnower, and the second-trial conviction of Carolyn Warmus in the “Fatal Attraction” murder of her lover’s wife.

As district attorney, he instituted branch offices throughout Westchester, ending a system that haphazardly handled minor crimes. Partly as a result, the number of assistant district attorneys grew from 17 to 109.

Among them was Jeanine Pirro, whom Vergari named to head a domestic violence unit. She succeeded him in 1994, served 12 years and is now the Republican candidate for state attorney general. He once accused her of “self-aggrandizement.”

Vergari, born in Yonkers, graduated from Fordham University and St. John’s Law School, with time out for combat as a Marine in World War II. For 10 years he was a prosecutor in the Manhattan district attorney’s office, and for another 10 years he was on the State Investigation Commission.

In 1968, he was appointed Westchester district attorney by Gov. Nelson Rockefeller to fill a vacancy. When he left office, he continued working at law firms until retiring to his winter home in Florida.

Vergari is survived by his wife Genevieve; his daughter, Jeanne Martinelli; and four grandchildren.