After the arrest of Iqbal Kaskar, brother of Dawood Ibrahim, two close aides of Kaskar were arrested today in connection with the extortion case, senior police official said. Mumtaz Sheikh and Israr Ali Jamil Sayyad, the associates of Kaskar were formally arrested today, they were earlier detained by police, Param Bir Singh, Thane commissioner of police said.Kaskar along with his associates were allegedly threatening a builder in Thane since 2013 and were said to have extorted Rs 30 lakh and four flats from the builder, news agency PTI reported. The police officer added that Iqbal Parkar, a close relative of Haseena Parkar and Mohammad Yasin Khwaja Hussain were also detained in connection with the case. Iqbal Kaskar, brother of Dawood Ibrahim, was arrested on Monday evening by police in Thane on extortion charges. Maharastra police said that demonetisation had helped in the arrest of Iqbal Kaskar.