With the ethnic and religious cleansing currently going on in some parts of the country,couple with power of incumbency,and desperation of buhari whose sympathizers have been killing people during the past years that he contested election and lost election,i don't think the election will be credible.
There is underage voters who have been line up to cast their votes for him.
The fear of prosecution of APC members:-Buhari will not want to relinquish power for fear of he and his members of being prosecuted for corruption as he has being selective with his anti corruption fight.