The Central Bureau of Investigation (CBI) has filed charges against five further people including jeweller Mehul Choksi as part of a probe into an alleged $2 billion fraud at state-run Punjab National Bank (PNB), two sources said.

The CBI named Choksi, three of his companies and four employees working at those companies in a charge sheet filed at a Mumbai court on Wednesday.

In a statement, the CBI confirmed it had filed a second charge sheet in the case, dubbed the biggest fraud in India’s banking history, but did not name the accused.

On Monday, it had filed charges against 22 people including jeweller Nirav Modi, former PNB chief Usha Ananthasubramanian, two of the bank’s executive directors, and three companies belonging to Nirav Modi.

Both Modi and Choksi have denied any wrongdoing. Ananthasubramanian and the two PNB executives did not reply to multiple calls and messages seeking comment.

The charges filed on Monday are the first formal ones to be filed in the sprawling case that has stunned investors, shaken the Indian banking sector and prompted a major regulatory crackdown.

PNB, India’s second-largest state-run bank, said in February that the two jewellery groups led by Modi and his uncle Choksi had defrauded it by raising credit from overseas branches of other Indian banks using illegal guarantees issued by rogue PNB staff over several years.

PNB has been conducting a separate internal probe into the fraud and has already suspended over 20 officials.

The fraud this week dragged PNB into a $1.98 billion fourth-quarter net loss, the worst loss ever recorded by an Indian bank.