A financial controversy involving an Indian cardinal has taken another turn after his archdiocese demanded a federal investigation into allegedly fake documents it said are aimed at defaming him.

A letter from the Syro-Malabar Archdiocese of Ernakulam-Angamaly, read at parishes May 26, said the archdiocese asked India's Central Bureau of Investigation to investigate the documents in a case involving Cardinal George Alencherry, ucanews.com reported.

The letter followed the arrest of Adithya Valavi, a Catholic software engineer, who is accused of fabricating documents about the cardinal under instructions from a group of archdiocesan priests.

The archdiocese's correspondence countered the police claims.

"None of our priests have either inspired or conspired to create such documents. All other campaigns are against facts," it said.

In November 2017, a group of priests accused Cardinal Alencherry and two priests of selling land and incurring a loss of about $10 million for the Kerala-based Eastern-rite church.

The Vatican in June removed the cardinal from administrative responsibilities in the archdiocese, but he continues to preside at liturgical and sacramental celebrations. He also continues to lead the church's decision-making synod based in Ernakulam.

In addition, the Vatican removed three prelates from administrative duties in the archdiocese, which has been experiencing infighting and financial controversies aggravated by disputed land deals.

The Vatican then appointed Bishop Jacob Manathodath as apostolic administrator of the archdiocese.

In February, a priest who is a junior official of the synod filed a criminal complaint accusing Bishop Manathodath and Father Paul Thelakat of forging documents to defame the cardinal.

The complaint said Father Thelakat forged documents showing that the cardinal had transferred money from his private bank accounts to corporate accounts. Bishop Manathodath was accused of presenting the documents to the synod with the intention of tarnishing the cardinal.

The complainant wanted a police investigation into the "conspiracy" behind the attempt to defame the cardinal. The investigation led to the arrest of Valavi.

"But we have reasons to suspect that the investigation is flawed. The truth behind the alleged fake documents can come out only through an impartial inquiry," said Father Kuriakose Mundadan, secretary of the archdiocesan Presbyteral Council.

The archdiocese's letter to parishioners said the software engineer stumbled on documents concerning financial transactions of some bishops and shared some of them with Father Thelakat, who has been the church's spokesman for more than three decades.

The priest gave the documents "privately and confidentially" to his superior Bishop Manathodath, who passed them to the cardinal in confidence.

"It was Cardinal Alencherry who presented them in the synod" and sought an investigation to find the truth of them, the letter said.

After Bishop Manathodath and Father Thelakat were accused of conspiracy, Cardinal Alencherry wrote to the religious of the archdiocese to say that the bishop and the priest were named inadvertently and the case against them would be withdrawn, ucanews.com reported.

"However, that promise has not been fulfilled. Both of them continue to be accused," the letter said.

The arrested software engineer was illegally kept under police detention for more than 48 hours and police allegedly forced him to admit that he fabricated the documents under the instructions of some priests, the letter said.

"This is a blatant violation of human rights and an open challenge to the judicial systems," it said, adding that "the archdiocese genuinely believes the investigation is not on the right track."