Jakarta. The Jakarta police have launched an investigation into an alleged treason plot that incriminated defiant presidential candidate Prabowo Subianto, a document showed on Tuesday.

The police have named Prabowo supporter Eggi Sudjana as a suspect in the case, charging him with treason and spreading disinformation, according to an investigation notice dated May 17 that leaked to journalists on Tuesday. 

The notice also mentioned that Prabowo "has been reported to the police," but he has not been accused of the crime of treason. 

Sufmi Dasco Ahmad, the deputy chairman of the Great Indonesia Movement Party (Gerindra) – Prabowo's political party – confirmed the Prabowo camp has seen the notice. 

However, he rejected the accusation that the former Army general was in any way involved in a treason plot. 

"There is no [police] notice about Prabowo [being involved] in a treason plot. The notice is about Eggi Sudjana," Dasco said. 

"Prabowo is mentioned [in the notice] as a person who has been reported [to the police], but he is not a suspect, or even a witness in the case," he said. 

"There is no single fact that can link Prabowo to the treason allegations. As we all know, Prabowo always fights according to the law and constitution," Dasco said. 

Prabowo declared victory in last month's presidential election just hours after the ballot stations closed, and despite all reliable quick counts pointing to a double-digit win for the incumbent, President Joko "Jokowi" Widodo. 

Prabowo still refuses to concede the election, claiming a massive fraud in the election and creating polemics in the media to undermine the General Elections Commission (KPU) and the Constitutional Court, which have the final say in resolving election dispute. 

In the latest development, Gerindra, PKS and PAN – three political parties supporting the Prabowo-Sandiaga Uno presidential ticket – have refused to sign off on the official election result announced by the KPU early on Tuesday morning, that has Jokowi winning re-election with 55.5 percent of the vote. 

Andre Rosiade, a spokesman for Prabowo's campaign team, said under Indonesian election law, a presidential candidate cannot be convicted for his speech. 

"Prabowo is a presidential candidate, so he is protected by the law. He cannot be convicted [for his speech]," Andre said.

He also said there have been no words or actions by Prabowo that may lead to charges of treason or threat to state security.