Washington ? The 73-year-old great-grandson of Alexander Graham Bell was sentenced Friday to life in prison without parole for quietly spying for Cuba for nearly a third of a century from inside the State Department. His wife was sentenced to 5 1/2 years.

Retired intelligence analyst Kendall Myers said he meant his country no harm and stole secrets only to help Cuba’s people who “have good reason to feel threatened” by U.S. intentions of ousting the communist Castro government.

But U.S. District Judge Reggie Walton said Myers and his 72-year-old wife, Gwendolyn, had betrayed America and should receive heavy punishment.

“You never know what the effect will be” from stealing classified information, said the judge. Someone “could be killed.”

Justice Department prosecutor Michael Harvey said the couple received medals from Cuban intelligence and were flown to the island nation for a visit with Fidel Castro in 1995. They pleaded guilty last November.

The couple’s overriding objective was to help the Cuban people defend their revolution, Myers told Walton. He said that he and his wife tried to accurately report what U.S. policy was toward Cuba, to warn Cuba and to try to assess the nature of any threat.

“At the expense of the United States,” Walton interjected.

In a sentencing memo to the judge, prosecutors said Myers, a descendant of Bell, was a child of wealth and privilege, and “could have been anything he wanted to be,” they wrote. “He chose to be a Cuban spy.”