The four arrested include two personal security officers of Mr Chadha and two office employees. The police, however, did not disclose their names.
The total number of arrests now adds up to six. Two other employees of Mr Chadha, Madan Rana and Vijay alias Malik, were arrested on Monday.
Mr Chadha and his brother Hardeep died in a shootout in a south Delhi farm on Saturday. A property is said to be at the heart of the dispute.
The three Chadha brothers - Ponty, Hardeep and Rajinder - were jointly managing the estimated Rs. 6,000-crore Wave Inc, formerly the Chadha Group, which has diverse business interests in fields ranging from distilleries, multiplexes, sugar to paper mills. Mr Chadha was thought to have been close to several prominent politicians. He hit the headlines in February this year when income tax officials conducted searches at his premises in Delhi, Noida, Moradabad and Lucknow.
(With inputs from IANS)