This has come two days after the Supreme Court allowed the central agency to take over the case.
The 10-member team, led by SP Nupur Prasad, had reached the city last night for the probe.
Here are more details.
Sushant's cook, one of the key witnesses in the case, has been questioned by the CBI officers.
Agency officers also visited the office of the Deputy Commissioner of Police (DCP) near the Bandra Police station.
Notably, CBI officers will collect all the case records and evidences including the autopsy report of the late actor from Mumbai cops, who had earlier been probing the matter.
Meanwhile, forensic experts from the CBI's Central Forensic Science Laboratory are also expected to visit the actor's house today.
Earlier, accused Rhea Chakraborty had filed a petition in the apex court, seeking to transfer case from Patna to Mumbai.
While pronouncing its verdict, the Supreme Court said that an impartial probe by the CBI was the "need of the hour." The top court also noted that growing allegations of political interference between Bihar and Maharashtra could potentially derail the probe.
Sushant's death case, earlier being probed by Mumbai Police, took a drastic turn after the actor's family filed a police complaint against Rhea, actor and Sushant's alleged girlfriend.
The 28-year-old actor has been accused of financial fraud and abetment to suicide.
The Enforcement Directorate (ED), which probes financial crimes, has also filed a money laundering case against her.
However, she has denied the allegations.
Sushant, aged 34, was found dead at his apartment in Mumbai on June 14. The Mumbai Police had termed it a case of suicide.
They revealed they found medications meant for clinical depression from the late actor's home.
Widely considered as one of most promising young actors, Sushant starred in movies such as Kai Po Che!, PK, M.S. Dhoni, Kedarnath, Sonchiriya, and Dil Bechara.
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