Right-wing group, the Federal Freedom Party has called for the treason case against two of its members to be investigated by international criminal police organisation, Interpol.
Four people were arrested after they were caught with ammunition and explosives in their possession.
It emerged they were hatching a plan to kill ANC leaders at Mangaung.
Party officials have thrown their weight behind the men who allegedly hatched a plan to bomb the national African National Congress (ANC) conference in Mangaung last week.
The FFP's Francois Cloete said the pair were wrongfully accused.
“We were really surprised that our members were in court, we still believe they are innocent. We don’t believe they were involved.”
He said party leaders want the international crime busting body intervene.
“We want an international opinion because it is an objective opinion. We don’t want a one-sided opinion and the South African Police Service (SAPS) is a government funded organisation. We want a neutral opinion to get the truth out of this whole case.”
Free State police at the weekend said they expect search warrants to be issued and more arrests to be made in the conspiracy to bomb a tent at the African National Congress Mangaung conference.
Authorities have neither confirmed nor denied reports that they were investigating a man from Springs who is believed to have masterminded a plot to attack ANC leaders in Bloemfontein.
The City Press revealed that a police reservist named Jaco Scherman, who calls himself the 'Boere Ninja', has been training a right-wing militia.