What official is at the Port of Entry?

[vtbngyn]

I read elsewhere that someone was allowed to enter the U.S at the POE, but when he/she applied for Naturalization, the USCIS found out he/she left the US for an extended period (lost PR status) the USCIS had to deport that person.

1. Who is at the POE? USCIS, State, or Custom official?
2. How come the official at the POE allowed him/her to enter at first?
3. Is there a USCIS database at the POE?

 

[TheRealCanadian]

Who is at the POE? USCIS, State, or Custom official?

Customs and Border Protection.

How come the official at the POE allowed him/her to enter at first?

They didn't do an exhaustive check of all of their travels.

Is there a USCIS database at the POE?

Yes.