Police on Tuesday questioned a relative of union minister MK Alagiri in connection with their search for his son, Durai Dayanidhi, against whom a case has been filed in the alleged illegal granite quarrying scam.
Police said they questioned Alagiri's son-in-law Venkatesan who responded to their summons.
Police were also questioning some close associates of Dayanidhi, sources said.
The Madurai Bench of the Madras high court had on September 25 rejected Dayanidhi's anticipatory bail plea in the multi-crore illegal granite quarrying case.
Dayanidhi, for whom a special police team was on the lookout, and nine others are facing charges that companies owned by them mined sand and granite without permission.
Police had charged Dayanidhi and Nagarajan, partners in Olympus Granites Pvt Ltd, with encroaching on government land and taking away large quantity of granite illegally without quarrying in the permitted area.
More than 20 persons have been arrested in connection with the illegal quarrying by various granite companies including PRP exports and Olympus granites.
Government cracked down on the firms after former Madurai Collector U Sahayam in a report, estimated the losses incurred from illegal granite mining at around Rs. 16,000 crore.