THANE/MUMBAI: Fugitive gangster Dawood Ibrahim 's younger brother Iqbal Kaskar , who was arrested on Monday from his Pakmodia Street residence along with two accomplices — real estate agent Mumtaz Shaikh and one Israr Ali Jamil Sayyad - for issuing extortion threats to a builder, is believed to have collected around Rs 100 crore from developers and jewellers in the Thane region in the last three years, a police officer said.Police are also probing the role of two local NCP leaders who allegedly acted as middlemen between Kaskar and the builders.Thane police commissioner Parambir Singh said they were also probing if Dawood himself was part of the extortion racket and if money was transferred to him through hawala, an illegal money transfer route. He added that a few local politicians who were aiding Kaskar in his extortion activities were under the radar."Recession and demonetisation hit builders badly, prompting Kaskar to also accept extortion in the form of flats," a police source said.Thane police chief Parambir Singh said Iqbal Kaskar has been threatening prominent builders in the Thane belt since 2013 and in one case had extorted Rs 30 lakh from a builder and also taken possession of four spacious flats in the plush Rosa Bella complex along Ghodbunder Road, whose cumulative worth is close to Rs 5 crore. While the gang disposed of three of the flats for Rs 30 lakh each sometime ago, the fourth flat was occupied by Kaskar aide Shaikh, the real estate agent. "Of the four flats, three have been sold," confirmed senior inspector Pradeep Sharma who was part of the team that carried out the arrest.One of the two local NCP leaders reportedly stood 'guarantor' on behalf of the builders, sources said. But NCP leader and spokesperson Nawab Malik told TOI the allegations were mischievous, false and baseless.Singh said preliminary investigation had revealed the names of certain big builders who were part of the criminal syndicate as they helped the gang get the ransom and would use their connections to evict other builders and grab land parcels. "Our probe so far has indicated that the gang would demand cash, flats, and also land from the victims. They had even extorted money from a jeweller and in one case in Navi Mumbai, a builder who was pestered left the city due to fear of the Dawood gang," he said."Till date we have (received) at least ten complaints against them, and they have been arrested in one offence registered with the Kasarwadavli police station by a builder Jain," Singh said."Kaskar and his aides threatened prominent builders demanding cash or the surrender of flats in their complex. The gangsters with the help of some politicians were also indulging in landgrab. We have tried to persuade most victims to report these threats," Singh added.Sources said Kaskar initially started settling property and financial disputes in the Thane, Ulhasnagar and Dombivli belt when he realised the area's "potential."Police said Shaikh, with the help of Israr, used to collect information about properties and pass it on to Kaskar. Police have detained the brother-in-law of Kaskar's late sister Haseena Parkar and another person who is said to be dealing in drugs. "We are interrogating them on their role," Singh said. Singh said they are taking also legal opinion on whether the stringent MCOCA can be invoked in this case. Thane magistrate R T Ingle remanded all three accused in police custody for eight days on Tuesday.Sources from Dubai said Dawood has passed on information to his aides in Mumbai and has asked them to have the best legal team to fight the case.