Iqbal Kaskar, brother of Dawood Ibrahim Kaskar, was on Monday arrested by the Thane Police Crime Branch.
Reports say that Kaskar, who stays in Bhendi Bazaar, was arrested from his residence in connection with a case registered against him by a Thane-based builder.
According to the builder, on Kaskar's demand, he had paid him some money in the past. When his demands did not stop, the builder approached the police.
The Thane Anti Extortion Cell is currently headed by Senior Police Inspector Pradeep Sharma, a former encounter specialist who was recently reinstated in the Maharashtra Police and posted in Thane.