The former head of the Peruvian intelligence service, Vladimiro Montesinos, has appeared in court to face the first of 57 charges brought against him.
Montesinos sat stiffly in court next to his ex-mistress
It is the first public trial for Montesinos, who was sentenced to nine years in jail at a closed-door hearing last July for abuse of power.
Montesinos is variously accused of drug-trafficking, embezzlement, corruption and involvement with death squads.
The former spy chief is blamed for the downfall of Alberto Fujimori, whose presidency collapsed in 2000 shortly after the discovery of a videotape apparently showing Montesinos bribing an opposition politician.
The first day of what has been dubbed in Peru as the trial of the century ended without a single word from the man accused.
It is the beginning of the public trial of probably the most corrupt man in the history of Peru
Investigator Ronald Gamarra
Looking noticeably greyer than the last time he appeared in public, Montesinos, 57, sat stiffly next to his former mistress Jacqueline Beltran.
He is accused of helping her brother get out of prison.
Answering questions from the prosecution, an emotional Ms Beltran denied ever asking favours from Montesinos.
"He just wants to avoid trial at the cost of my suffering ...It's revenge just to make sure I'm locked up," she said.
Montesinos was flown by police helicopter from a naval prison to the heavily guarded Lurigancho courtroom.
Around 1,000 police officers were said to have lined the route to the specially constructed jail, which was surrounded by sharpshooters and mounted police.
"We are talking about the head of an organisation that I think still has its tentacles out there," said Ronald Gamarra, a state attorney assigned to the corruption investigations.
Security around Lurigancho prison
"I imagine there are people interested in keeping his mouth shut. That's why we have to take security measures," the news agency AP quoted him as saying.
Montesinos fled Lima during the Fujimori scandal, and was arrested in Venezuela in June 2001.
At his trial, Montesinos - in a silk shirt - entered a written statement exercising his right to remain silent and questioning the impartiality of the judges.
His lawyer, Estela Valdivia, has so far failed to have charges of influence-peddling set aside.
After five and a half hours, the trial was adjourned until Thursday.
Correspondents say the investigations into his alleged criminal activities could produce Peru's most complicated prosecution.
They add that the case is likely to be controversial, as many in Peru believe that Montesinos still holds great power over a judicial system he controlled under Mr Fujimori.
Reports suggest some judges fear that Montesinos may have access to incriminating videotapes of them.
Many of Montesinos's alleged corrupt dealings were captured on videotapes he made.
"It is the beginning of the public trial of probably the most corrupt man in the history of Peru... finally, after two years," Mr Gamarra said in a radio interview.