A Bolivian former seminarian who says he was the victim of a vast sex abuse network in the Catholic Church has told AFP of decades of "hell" meted out to children by men of the cloth.

Pedro Lima said not only minors but also adults like himself who were training to become priests were subject to abuse in the South American country, often by clergymen who arrived from Spain.

The 54-year-old, who has lived in Paraguay since 2011 where he works as a blacksmith, returned home last month to give evidence in a vast investigation into child predation at schools countrywide, including a boarding school for poor, rural kids in Cochabamba.

"The children lived through hell," he recounted of things he said he saw. "These abusive priests were saints by day, demons by night."

At the center of the latest scandal is a Spanish priest by the name of Alfonso Pedrajas, who died in 2009 after decades of service as a Church teacher in Bolivia starting in 1971.

In his journal, recently discovered and published by a newspaper, Pedrajas confessed to having harmed dozens of people, possibly as many as 85. He also noted that senior clergy had known about his crimes and kept quiet.

Lima, who said he had encountered Pedrajas personally, claims he was expelled from the Jesuit order in 2001, while studying to become a priest, for reporting abuse.

Since then, he has compiled a list of alleged wrongdoers, most of them now dead.

"It wasn't only one priest, there is a structure of priests who helped and supported each other so this (abuse) could continue to happen," he told AFP.

Priests heard young victims' complaints, then rebuked them and expelled them from school, Lima alleged.

He said he, too, was a victim, but declined to go into detail given the "pain" it causes him.

"Those types of acts that have been committed against other people have been also perpetrated against me," Lima said.

- 'Brainwashed' -

Spanish priest Jordi Bertomeu, a top sex crimes investigator for Pope Francis, has been investigating the claims in Bolivia, a country of 12 million people who are mostly Catholic.

According to Lima, the aggressors "brainwashed" vulnerable children who were made to believe they were "the bad guys and worthless."

The Bolivian Episcopal Conference, which last month admitted having been "deaf" to the suffering of victims of pedophile priests, declined to comment on Lima's specific allegations.

Since the revelations in the diary, Bolivian prosecutors have opened cases against priests including Pedrajas and three others from Spain: Luis Maria Roma, Alejandro Mestre and Antonio Gausset.

All four are deceased, but there are other accused still alive.

Several alleged victims have come forward in recent weeks in the capital La Paz, in Cochabamba, Tarija in the south and Santa Cruz in the east.

A recent investigation by Bolivian newspaper Pagina Siete finding at least 170 alleged victims.

Bolivian President Luis Arce has written to Pope Francis to ask for any files on sexual abuse committed by Catholic priests in the South American country.

Lima, for his part, is seeking "full reparation" from the Church.

There are "broken people, totally, whose lives were destroyed by the aggression, people who have ended up needing psychiatric (treatment)," Lima said, though he himself came through it OK.

"The damage is great."

Thousands of reports of pedophilia within the Catholic Church have surfaced around the world in recent years.

Pope Francis has pledged an "all-out battle" against clerical abuse, holding an unprecedented summit on the issue in 2019 and enacting reforms that include new obligations to report clerical child abuse and cover-ups.