USPS opening a domestic package.

So i sent a package to a member here and all went well with everything except, he gets the priority mail box and it had been opened by the USPS. they opened it, removed two of the coffins and replaced them with a note and some type of quit smoking tips.

is there any repercussions to the post office about this, or the employee? they blatantly stole something of mine and replaced it. i'm waiting for the box to get back to me to take it to the post office but would like everyone's opinions on what i should do. should i talk to the post master? i don't ship insured, only with a DC# usually as i don't expect the USPS to steal anything. especially a small priority mail box.