Former Burundi leader Domitien Ndayizeye and six others have appeared in the Supreme Court on charges of plotting to assassinate the president.
President Domitien Ndayizeye (l) handed over power last August
Reporters were barred from the courtroom, Reuters news agency says.
The court has 48 hours to rule on a defence request for the suspects to be freed on bail.
Earlier, the man at the centre of the alleged coup plot withdrew his claims, saying they were extracted under torture by the security services.
Alain Mugabarabona told local radio stations by phone from his prison cell that he was threatened with death.
"This coup story has been invented by the Documentation Nationale," said Mr Mugabarabona , referring to Burundi's powerful presidential police and intelligence service.
"Everything I accused former President Domitien Ndayizeye, former Vice-President Alphonse-Marie Kadege and the others of was extorted by torture and threats," said the official of the rebel National Liberation Forces (FNL).
Information Minister Karenga Ramadan, however, denied that the charges had been fabricated, telling the BBC that the authorities had strong evidence of a genuine coup plot in which nine arrested people were implicated.
The FNL is the only rebel group which remains outside a peace process intended to end 13 years of ethnic conflict between Hutus and Tutsis.
Mr Ndayizeye, a Hutu, was leader under a power-sharing agreement before stepping down last August after elections.
He was succeeded by Hutu former rebel leader Pierre Nkurunziza.