POUGHKEEPSIE, N.Y. — A former Soviet fighter pilot who defected to the U.S. in the late 1980s has been sentenced to 18 years to life for robbing an upstate New York bank for a second time.

Alexander Borisov was sentenced Thursday by a Dutchess County judge who wondered why the 47-year-old Russian turned to robbing banks in the early 1990s, about two years after defecting from the Soviet air force in Afghanistan.

Borisov was sent to prison in 1992 for robbing the First Niagara Bank in Millerton, N.Y., in December 1991 and then served time in Connecticut for robbing two banks there in January 1992.

He was released from prison in 2007, but two years later was arrested again for robbing the Millerton bank. He pleaded guilty in March to first-degree robbery.