In your second year they will have you decide a major.

If you want forensic criminology, then a law enforcement degree (even a two-year associate’s) with a load of chemistry, biology and physics courses as electives–or major in one science and minor in law enforcement–that would be a good start. You’d probably do police academy and spend some time as a street cop in order to get on-the-ground experience with crime scenes and investigative procedures.

If you want forensic pathology, then you’re going to need to get into med. school, become a general practitioner, then return to med. school for further study in pathology, and then pass state boards for the specialists’ license. Then your work will probably center on general pathology in some hospital, where you’ll do the post-mortem “cause of death” work that the police investigation shows have so ridiculously placed in police HQ–and also you’ll spend a lot of time looking at tissue samples under microscope to determine if they’re cancerous, etc.

Then there are the forensic investigators who look into air crashes–

Forensics is mainly science – chem, bio, or even physics.

You’d be better off majoring in one of those, then specializing in forensics later on.