The Central Bureau of Investigation - India's federal investigators - have arrested three of Satyam's financial staff they believe were involved in the fraud.

The beancounters are suspected of helping Satyam's founder Ramalinga Ramu forge documents to provide evidence of inflated revenues to auditors. Ramu wrote a bizarre letter to directors admitting bolstering revenues by $1.5bn.

The investigators said in a statement: "A lot of incriminating documents have been retrieved from these accused establishing their complicity in the crimes. Further investigation is continuing."

Reports suggest the CBI has now charged nine people in total - Ramalinga Ramu, his brother Rama Raju, four other Satyam staff, an outside adviser and two auditors from PwC.

Investigators presented thousands of pages of evidence and claim to have 432 witnesses. ®

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