Tonye Cole, the governorship candidate of the APC, polled 95,274 votes to come second.
Mr Chisom Lennard was killed on Saturday while trying to prevent thugs from hijacking ballot boxes and other election materials.
He said that it was important to note that the Labour Party stands by all its candidates in this election and it is not in alliance with any party.
The LP presidential candidate made this claim in an interview with Arise TV Monday morning.
He, therefore, called on security agencies, the Inspector General of Police (IGP) to investigate the allegations and avert the plan.
The Rivers governor said Mr Obi’s candidature blocked northerners from retaining power after President Muhammadu Buhari’s eight years in office.
Mr Amaechi also urged the residents of the state to protect their votes on election day.
The council said the decision was part of the resolutions reached at its meeting on March 9.
“The issue of (zoning the) presidency to the South-East was never on the table.”
Eleven per cent proposed to vote for Senator Magnus Abe of the Social Democratic Party (SDP) who fell in second place, adding that Tonye Cole of the APC candidate was third with 10 per cent.
