FORT LAUDERDALE, Fla. AP – A former banker described by prosecutors as the man most responsible for sparking a broad U.S. investigation into rich Americans’ use of secret Swiss bank accounts to evade taxes was sentenced Friday to more than three years in federal prison.

Prosecutors gave Bradley Birkenfeld, a 44-year-old U.S. citizen, credit for voluntarily disclosing illegal tactics by Swiss banking giant UBS AG and others. But they said Birkenfeld initially refused to confess his own misconduct in hopes of collecting a cash reward under U.S. whistleblower laws.