After launching the investigation in the mysterious death of actor Sushant Singh Rajput on Friday, CBI questioned a few key witnesses and also collected the case diary from the Mumbai Police to begin their examination. The collected documents included Sushant’s five diaries laptop, three mobile phones, recorded statements of the people related to the actor, the clothes he was wearing that day, the cloth with which he allegedly hung himself etc. Mumbai Police during their investigation had questioned 56 people related personally and professionally to Sushant. CBI on Friday examined Rhea Chakraborty’s brother Showik’s statements and is likely to call him for questioning today. The SIT team of CBI has also summoned the late actor’s flatmate Siddharth Pithani as well as domestic staff Dipesh for questioning. They are the prime witnesses in the case. Pithani was the one who allegedly brought the actor’s body down on the bed after he found him hanging.