Kaskar's driver-cum-bodyguard Arif Sayed was shot dead in May, 2011 on the ground floor of Kaskar's residence on Pakmodia Street in south Mumbai.
"Iqbal Kaskar today deposed as a witness," said an official of the Mumbai police's crime branch.
Kaskar told the court that he was resting in his house at the time of the incident. He heard people shouting and was later informed that there had been a firing.
When he came down from his house, he saw a blood stain on the stairs and an empty cartridge, he said.
Rajan, Dawood's arch-rival, is believed to be holed up in a South East Asian country. His close aide D K Rao was arrested in the case.