The firm of Crull, Castaing & Lilly is a full service law partnership with primary emphasis in criminal law and civil litigation. The firm was founded by F. Irvin Dymond (1914 - 1998), who graduated from Tulane Law School in 1937 and began practicing law in New Orleans. With the outbreak of World War II, he entered the war as a naval officer and saw combat in both the Atlantic and Pacific campaigns. His ship, USS Bismarck Sea, was sunk at the Battle of Iwo Jima in 1945. Following the War, Mr. Dymond returned to New Orleans and resumed his law practice in the First National Bank of Commerce Building, 210 Baronne Street.

Mr. Dymond was joined in 1960 by William L. Crull, III, who had just graduated from Loyola Law School after serving as a Navy Officer in the Korean conflict and then engaging in the insurance business. Together, Irvin and Bill became legendary in the field of criminal law and general litigation. In particular, Mr. Dymond gained national recognition for his successful defense of Clay Shaw in 1969, who had been charged by District Attorney Jim Garrison with conspiracy to assassinate President John Kennedy. Mr. Dymond was the Dean of New Orleans criminal trial practioners for many years.

The firm remained in the First National Bank of Commerce Building until 1993, when it relocated to One Shell Square, 701 Poydras Street. In 1998, the firm moved to Pan American Life Center, 601 Poydras Street, Suite 2323, New Orleans, Louisiana, where it remains today. The Pan American Life Center is located caddy corner from the U.S. District Court for the Eastern District of Louisiana.