I had applied for DHS TRIP and they closed the case and sent me a letter but it hasn't reached me. It has now been 10 days. I actually have two addresses and dont remember which one i had put in while filling the form. Can I track it?
If they sent it with a courier service (Federal express, ...) they should have given you a tracking number, then you can check on their web site.
If they sent it by regular mail, then it is hard to track, and can take a long time, especially in India.
I'd wait for another week, and check both addresses if you can; after that, you could contact the DHS and inquire about it.