Peru's feared ex-spymaster Vladimiro Montesinos, known as the "Rasputin of the Andes," is in the spotlight after being caught trying to manipulate the outcome of June 6 presidential elections from prison.

In recordings released last week, Montesinos instructs retired military commander Pedro Rejas to arrange bribes for judges on the national electoral jury to proclaim Keiko Fujimori the winner over rival Pedro Castillo.

Corruption-accused Fujimori is the daughter of Montesinos's old boss, ex-president Alberto Fujimori, himself in prison for graft and rights abuses.

The younger Fujimori, who alleged vote fraud as Castillo took the lead in the ballot count, risks an imminent trial on corruption charges that would be delayed until after her term if she were to win the presidency.

Montesinos, 76, has served 20 years of a 25-year sentence in a maximum security prison on a naval base for arms trafficking and corruption committed during Fujimori's presidency.

On Saturday, ex-lawmaker Fernando Olivera revealed seventeen recordings exposing Montesinos's alleged bid to interfere in the presidential vote.

The navy and prison authority have confirmed the authenticity of the recordings and launched an investigation.

In one recording, Montesinos is heard telling Rejas to "make them understand, the father or the girl -- I don't know whom you are talking to -- that... we are trying to help in a common objective" referring to the Fujimori duo.

"What do I gain?" he continues. "Nothing... I am simply trying to help because if not they will screw themselves, the girl will end up in prison."

The younger Fujimori said she listened with "indignation" to the calls "from a man who betrayed all Peruvians."

Peru's ex spy chief Vladimiro Montesinos has served 20 years of a 25-year sentence in a maximum security prison
Peru's ex spy chief Vladimiro Montesinos has served 20 years of a 25-year sentence in a maximum security prison AFP / JAIME RAZURI

She has always maintained that Montesinos had acted behind her father's back, and has vowed to pardon her parent if she becomes president.

Peruvians have been made to wait more than three weeks for the results of the deeply polarizing election that had rightwing Fujimori neck-and-neck with rural school teacher Castillo, a leftist trade unionist.

According to the count, Castillo received 50.12 percent of votes -- some 44,000 more than Fujimori.

The United States, European Union and Organization of American States have all said the election was free and fair.

But Fujimori has cried foul, demanding a review of thousands of votes by the national electoral jury, which is still under way. The jury will ultimately declare a winner.

The man who released the recordings, Olivera, is the same who in 2000 released a video showing Montesinos bribing an opposition MP to join Fujimori's ruling party to give it a majority in Congress.

That video was the catalyst for the impeachment of Alberto Fujimori and forced Montesinos to resign.

Montesinos was Fujimori's right-hand man during his 10 years in power from 1990 to 2000, converting the secret police into a political arm of the president's party and leading a merciless fight against Maoist rebel group the Shining Path.

Arrested in 2001 after months on the run following the video's release, Montesinos was sentenced to a quarter-century in prison.

He had previously served jail time in the 1970s for his involvement in the presentation of classified information to the CIA on Soviet armaments acquired by Peru, and for falsifying a signature to travel abroad.