He joined the department in 1995, and rose to fame as an encounter specialist in the late 1990s, as a member of the Detection Unit.

[3] Nayak himself disapproved of the sobriquet "encounter specialist", insisting that he is not a trigger-happy man but was forced to kill gangsters to prevent more "bloodshed and mayhem".

The school was inaugurated by Amitabh Bachchan in 2000 in presence of celebrities like M. F. Husain, Suniel Shetty and Aftab Shivdasani.

In 2003, Ketan Tirodkar, a journalist, accused Daya Nayak of having links with the Mumbai underworld, and of amassing wealth disproportionate to his income through illegal means.

[7] Nayak was investigated by the Maharashtra Control of Organised Crime Act (MCOCA) court for links with the underworld.

The same year, Tirodkar was taken into custody on the charge of having links with the Dubai-based don Chota Shakeel.

[8] In 2006, Nayak was arrested during an investigation led by the Anti-Corruption Bureau (ACB) ACP Bhim Rao Ghadge.

[9] Nayak was accused of floating bogus companies with help of his associate Rajendra Phadte, and getting his wife Komal to take property loans.

The ACB alleged that Nayak had transferred ₹ 1 billion to a foreign contact from a cyber café in Goa.

It claimed that he was in Goa on 18 January 2006, but his duty records proved that he was at the Charkop Police station.

ACB also brought up the point that a person called D Naik had travelled several times between Mumbai and Goa by air.

[13] The transfer order was cancelled in August 2015, and Nayak was reinstated in Mumbai Police on 11 January 2016.

The 2012 Bollywood film Department highlights the encounter specialists of the Mumbai Police; Daya Nayak's role is played by Sanjay Dutt.