Address, FBI, Criminal Background
I believe INS does the following verification in coordination with the agencies such as FBI etc.
1. Verification of addresses mentioned for the last 5 years in your
application
2. Criminal background check with the law enforcement agencies
3. Background check with help from FBI. FBI uses the finger prints
to match it against their database.
4. Applicant\'s involvement with banned organizations such as
Al Khaida
It is based on my own understanding. These things are not well known
and understood. We can only speculate what they do. Bottom line is
that there is process (and hence, a delay) involved with the
background check.