The chargesheet was filed before CBI judge Narendra Dutt here on Tuesday, Dec 22.
The investigating agency also filed murder charges against seven police personnel for allegedly kidnapping and killing Singh on Jul 3.
All the seven police personnel, who are facing murder charges include GD Bhatt, Santosh Jaiswal, Nitin Chauhan, Rajesh Bist, Neeraj Yadav, Chandra Mohan (all Sub-inspectors) and constable Ajit Kumar.
Besides filing murder and kidnapping charges under section 302 of the IPC, the CBI also accused all the 18 police officers of tampering with evidence.
After making a thorough assessment, CBI had reached a conclusion that Singh was killed after being subjected to torture.