The 29 colleagues of Basu had also gone on the picnic, which was organised on motor-launch MV Shibani.
Basu, who had allegedly fallen from the launch into the river in the afternoon, is yet to be found.
The 29 employees of Floatel had moved anticipatory bail petitions in the high court on the ground of a reasonable apprehension of arrest by the police.
The police had lodged a murder case on the basis of the FIR and were questioning Basu's colleagues regularly, he told the bench.
The state's counsel submitted that the police were trying to trace Basu and that the probe was progressing.
The bench directed the police not to arrest the 29 persons for a period of two months and directed them to cooperate in the investigation.