Question About Additional Background Checks

[Conyers]

Yesterday, Both my husband and I had Citizenship interviews. I passed and swore in the same day. My husband also passed the test, but was told that FBI needs additional background checks, so the case is pending. Can anybody help me to answer the following questions. Thanks thanks a lot.

1. Is this happened often?
2. Why does FBI need additional background checks.
3. What do they check? (by the way, we came from China)?
4. Usually, It takes how long?

[immihelp]

1. No.
2. They might have found same bad records for the persons who might have same name as yours or very similar names.
If you did not do anything wrong, don't worry.
3. Mostly, criminal background.
4. Four to eight weeks.