Peter Mukerjea, former media baron and one of the accused in the Sheena Bora murder case, was on Thursday night taken back to Delhi from Mumbai by the Central Bureau of Investigation for possible polygraph and brain-mapping tests on him.

Peter was flown to Delhi at around 8 pm after the agency secured extension of his custody from a Mumbai court till November 30.

Sources said the CBI is looking into his alleged investments abroad and custodial investigation was necessary to further the probe. The sources also did not rule out the agency subjecting him to scientific tests like polygraph, brain-mapping etc.

Peter, 59, husband of prime accused Indrani Mukerjea, was arrested on November 19 and later taken to New Delhi for two days for questioning by senior CBI officials and experts on the financial trail in the sensational murder case before being brought to Mumbai on Thursday morning.