Unable to return to the fighting, Mr. Leavelle became a civilian employee of the Army Air Force, running a military warehouse in Riverside, Calif. He then became an auditor for the federal government, investigating colleges receiving money under the G.I. Bill.
He spent his first six years on the Dallas force in patrol before making detective in 1956, and worked his way up from the burglary and theft squad to homicide, where he was working when President Kennedy was assassinated on Nov. 22, 1963. Mr. Leavelle retired in 1976 and founded a polygraph business, which he turned over to his daughter Karla in 1980. He underwent triple-bypass heart surgery in 2004.
Mr. Leavelle, who remained active into his late 90s, traveled with the help of a Dallas police officer to the National Law Enforcement Museum in Washington in late 2018 to rerecord an oral history he had made several years earlier before the museum’s opening in October.
In his last years Mr. Leavelle served on the board of the Crime Stoppers organization in Garland, Tex., and continued giving talks to police and school groups, usually around the Nov. 22 commemorations. He was still making occasional appearances as late as 2018. He said that he received about 500 requests a year for his autograph — “more than I need” — and in a phone interview in December said he had “four or five on my desk” at the moment. He was particularly proud, he said, of an invitation to address the F.B.I.’s graduation of its October 2006 agent training class at Quantico, Va.
As late as January he lived alone and unassisted. At 98½, he fell while he was doing errands in Garland, but he got himself home and planned to see a doctor a few days later. “It’ll quit hurting in a little while,” he told a Times reporter by phone.
For years, the light-colored double-breasted suit that Mr. Leavelle wore in the famous photo gathered dust in his closet. He later lent it to the Sixth Floor Museum at Dealey Plaza, in the former Texas School Book Depository, from where Mr. Oswald is believed to have fired the fatal shots. It is displayed behind glass with his original hat, tie and handcuffs.
The boots on display are a later addition. He had thrown out the pair he was wearing on Nov. 22, 1963.
“I didn’t realize they were worth something,” he said.
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