Deepak Jadhav hanged himself to a ceiling fan of a room on the second floor of the building which houses the police station this morning.
"Jadhav had tied his neck with the trouser of a police officer's uniform," senior inspector of Mankhurd police station Nasir Shaikh said.
According to police, at 7.30 AM, Jadhav and Mohammad Naim (27) were brought to the police station as they were fighting with each other.
At this time sub-inspector Rajendra Londhe was on duty. After preliminary inquiry, at around 8 AM, Jadhav was let off by Londhe after giving a warning, an official at the police station said.
The Mumbai Police has handed over the case to crime branch.
"Considering the mysterious suicide, the crime branch is probing the case," said DCP (Detection) Dhananjay Kulkarni.