"I have been a labor slave and a sexual slave for a group of depraved people, who were protected by Church officials," an alleged victim of child sex abuse, now aged 36, has written in a letter to the Pope. "In the three years I spent at the mission in Nariokotome, in Kenya, I was treated like a beast of burden. There were around 30 people, and on top of the slave work there was the sexual slavery. They would tell us that an active sexual life is something that God wants, and that He also wants us to go around naked, because that is the way He made us. Help me, Francis. Soothe my broken soul a little. Don't let other youths endure this hell."

The distressing testimony of Paulino, a former member of a Barcelona Catholic religious group, The Missionary Community of Saint Paul the Apostle and of Mary (MCSPA), has been published this week by the Spanish newspaper El País.

El País says Paulino's seven-page letter is significant because it appears to have reached Pope Francis. The Vatican is understood now to be looking into this and other complaints about the group. 

Dominick Kimengich, the bishop who issued the licence that allowed MCSPA to operate in Kenya, wrote to El País: "I am aware of several accusations that were put to the Congregation for the Doctrine of the Faith and to the Pontifical Council for the Laity, but they seem to involve events that were investigated in 2006."

The group was founded in Spain by Francisco Andreo, who died of cancer two years ago, and others.

In 1995 there was a criminal complaint alleging abuse of minors and statutory rape. The case was shelved. Founders of the order, which has outreach in Latin America and Kenya, were reprimanded by the Archbishop of Barcelona. Andreo left Barcelona to work for the group in Africa and the United States. 

The Vatican investigated the group's work in Kenya in 2006 and concluded there had been no abuse.

Senior Spanish priest Fidel Blasco Canalejas, a prominent campaigner for justice for victims of sex abuse, said: "Why such fear of the truth, why so long before we end the suffering of so many people?" 

Paulino told El País: "To the fear, they added an intelligent brainwashing process. You're living in a desert, in a foreign country, without a passport, without any documents or money. You rely on them for everything, completely. You are their slave, and they abuse you. First they rip you away from your family. Then they make you believe you're a piece of s**t and that your job is to obey blindly."

He said Andreo would organise orgies with men and women, where he sometimes took part and other times watched. "When he wanted sex, Andreo would call a boy in to his room. The day he called for me, I arrived expecting the worst." When Paulino failed to respond, Andreo kicked him out. "I walked out with a broken soul – the scene is branded in my memory forever."

Asked by the Spanish newspaper to comment, individuals named in the dossier sent to the Vatican "vehemently denied" the accusations.

The group still has missions in Africa and the Philippines.

Christian Today reported this week that sex abuse scandals that have rocked the Catholic Church in the US have already cost the institution nearly $4 billion over six decades. Between 1950 and August 2015, the Church paid out nearly $1bn more than previously estimated.