ATTM Settlement Checks in Someone Else's Name coming to me

I received 2 separate letters coming to my PO Box (which I have had for about 14 years) that are to a person who has never had a PO BOX at this post office.  I am very weary of someone else's mail coming to my PO BOX as it may indicate a stolen identity.

What should I do?  How can I check if I was supposed to be receiving these (in my name) and there was an error?