“No lead was left unturned, even if it was unconfirmed or remote,” Mr. Schroeder said, including a trail of clues that led to an address in Portugal where Mr. Wright might have been living.

United States officials worked with Portuguese authorities to follow that lead, using the Portuguese national identity database, which includes fingerprints. The fingerprints that the authorities in the United States had for Mr. Wright matched prints on file from Mr. Dos Santos, Mr. Schroeder said.

“Then it was just a matter of basic police work, setting up surveillance,” he said.

In 1962, Mr. Wright was involved in a string of armed robberies. During one of them, at a gas station in Monmouth County, N.J., Mr. Wright shot and killed the owner, Walter Patterson, a World War II veteran and a recipient of the Bronze Star. Mr. Wright was caught a few days later and eventually sentenced to 15 to 30 years in prison.

He and three other men escaped in 1970, from Bayside State Prison in Leesburg, N.J.

In July 1972, Mr. Wright and four others hijacked Delta Flight 841 en route to Miami from Detroit. The passengers were exchanged for $1 million — the highest ransom of its kind at the time, according to the F.B.I. — and the hijackers demanded that the plane be flown to Algeria, where they hoped for asylum.