Kerwin Bollers says Monday's performance for Carnival celebrations was called off after e-mail and phone threats from an unidentified source.
Police Commander Leroy Bollers reporters Sunday that authorities will investigate.
T-Pain would have been one of the best-known U.S. singers to perform in the South American nation in years.
Legally named Faheem Najm, his stage moniker is short for "Tallahassee Pain" in reference to the Florida city where he was born.
He is credited with popularizing synthesizer-assisted vocals in R&B, and recorded the albums "Rappa Ternt Sanga" and "Epiphany."