The battle to control the Rs 30,000 crore Sona Group has taken a dramatic turn with it getting shifted to the United Kingdom this week after Rani Kapur, mother of late Chairman Sunjay Kapur's, hinted at a "transnational conspiracy" that led to the "murder" of her son, media reports said.

In a letter that NDTV has seen, Rani Kapur claimed she has "credible and concerning evidence... that suggests Sunjay Kapur's death may not have been accidental or natural, but may have involved foul play, including possibility of murder, abetment, conspiracy, fraud, and forgery".

She also claimed she has records that "point to forgery, dubious asset transfers and suspicious legal filings, (and) indications of collusion between individuals who stood to gain financially" from his death.

The reference was to Priya Sachdev Kapur, Kapur's third wife.

"There are compelling reasons to believe his death may have been facilitated or orchestrated as part of a coordinated transnational conspiracy, with the involvement of individuals and entities in the United Kingdom, India and maybe the United States," Rani Kapur told British authorities in her letter.

"Given the gravity of the matter and possible multiple offences under UK law, including murder, conspiracy to commit a crime, fraud by false representation, forgery... I respectfully request for immediate registration of a formal complaint and initiation of a criminal investigation," she said.

Identifying herself as the majority shareholder of the Sona Group, which includes Sona Comstar and Sona BLW, she said she had been "compelled to sign documents" while grieving for her son.

She questioned the decision to appoint "certain people (i.e., Priya Sachdev Kapur)", and said their claim to speak for the family was based on "documents executed by me under coercion".

She claimed to possess information that highlighted "gross illegalities" in company affairs.

Sona Group's flagship company, Sona BLW Precision Forgings Ltd, had, however, said that Rani Kapur, has not been a shareholder since 2019.

This comes after Rani Kapur wrote to the board, identifying herself as a majority shareholder and demanding that an Annual General Meeting scheduled for this afternoon be postponed.

The company responded with a market filing that said in May 2019 a "declaration of significant beneficial ownership" was received that identified Sunjay Kapur as the "sole beneficial owner...".

The company said Rani Kapur had "not been a shareholder since 2019".

On the appointment of Priya Sachdev Kapur as a non-executive director, the filing said her name had been proposed and her appointment was "duly reviewed... and approved".

Responding to Rani Kapur's claim about being "forced to sign documents behind locked doors", the board stressed that no documents had been signed or obtained from her since Sunjay Kapur's death.

Sunjay Kapur died of a heart attack on June 13. He was 53 and passed away while playing polo.

He was previously married to actress Karisma Kapoor in 2003 and divorced in 2005. They two had two children-a daughter and a son.

Sunjay later married Priya Sachdev and the couple had a son.