Buba Galadima, a national leader of the Peoples Democratic Party (PDP), has been released from custody.
Galadima was arrested by suspected security operatives during the presidential election on Saturday.
The All Progressives Congress Presidential Campaign Organisation had before then alleged he was plotting to announce Atiku Abubakar of the PDP winner of the election.
The PDP had raised the alarm over his arrest but Galadima was spotted at the press conference addressed by Atiku in Abuja on Wednesday.