The Bayelsa State governorship election tribunal sitting in Abuja on Monday annulled the election of Governor Duoye Diri.
The Tribunal in its ruling, ordered that fresh election be held within 90 days.
The Advanced Nigeria Democratic Party (ANDP) had asked the tribunal to cancel the election because it was excluded from the exercise.
Sen. Diri, candidate of the Peoples Democratic Party (PDP), was sworn in as governor after the Supreme Court sacked David Lyon as Governor-elect 24 hours before his inauguration in February.
