Hey prisha!

As  you want to know about colleges that are in  Tamil Nadu for forensic science , then B.Sc. forensic science is not available in the state govt. colleges. But there are other undergraduate programmes after which you can do M.Sc Forensic Science.The advantage of opting for such a degree is that the other career options are also open for you. Nevertheless, you can pursue a Masters in Forensic Science.

Also, there are some private colleges that provide undergraduate course related to this field such as 

Karunya Institute of Technology and Sciences, Coimbatore which provides B.Sc Information Security and Digital Forensics. 

Hope it helps!