Bolivia's investigation into a group of Europeans, including Irishman Michael Dwyer, who allegedly planned to kill the president and destabilise the country has worsened political and regional divisions as critics say the government's evidence is weak.
Bolivia, the poorest country in South America, has a long history of political instability.
But the alleged plot points to turmoil in the run-up to elections in December that President Evo Morales hopes will win him a second term in office and majority control of both houses of Congress.
Police killed Mr Dwyer (25), along with a Bolivian-Hungarian and a Hungarian in April in the eastern city of Santa Cruz, arrested two others and seized a weapons cache as they broke up what the government called an international terrorist ring.
Mr Morales, who has overhauled the constitution and increased state control over an economy dependent on exports of natural gas and minerals, said his right-wing foes in Santa Cruz had backed the group, whose members left behind Internet blogs about fighting communism and about separatist movements.
Conservative business groups and politicians in Santa Cruz have called for more autonomy for their region but vehemently deny any involvement with the group, whose leader, Eduardo Rozsa, fought in the war in the Balkans.
The only way to prevent the investigation from becoming completely politicized would be to find neutral parties to conduct it, said Jim Schultz, head of the Democracy Center think tank in the central Bolivian city of Cochabamba.
"Getting the actual facts of what happened is like wrestling a marshmallow," Mr Schultz said.
"We know that these people in Santa Cruz were up to something not especially democratic ... (but) the government has laid claims about what these guys were doing with some pretty squishy evidence."
Prosecutor Marcelo Soza defended the investigation, said that witnesses say two prominent Santa Cruz leaders, antigovernment activist Branko Marinkovic and Governor Ruben Costas, sponsored the group's activities.
"If I've given their names, it's because I have leads. I haven't made anything up," said Mr Soza.
But those demanding more autonomy for Santa Cruz say the investigation is a political vendetta.
"We categorically reject this government setup," Mr Marinkovic said last week. "It's totally untrue. It's a blunt attack against the autonomy (movement)."
The president's rivals have accused the police of killing the suspected mercenaries in cold blood, not in a shootout as the police reported.
An official involved in the investigation, speaking on condition of anonymity, said detectives hope to find more evidence against political and business leaders in Santa Cruz in five laptops the group carried with them.
"We hope to find elements that link these people (Marinkovic and Costas) or others in the computers, but terrorist cells usually avoid face-to-face contact," said the official.
"It's going to be difficult to prove (they met)."
Mr Marinkovic, a wealthy soy magnate of Croatian descent, is the political nemesis of Mr Morales, who hails from a poor family and wants to shift political power and wealth from a small European-descended elite to his indigenous power base.
Reuters