How do I check status of my investigation?

What number can I call to check status of my ‘expedited’ BI?
I have no idea of any ‘identifying’ numbers for my case…
This is for a BI job with SCIS.

I guess I answered my own question…according to OPM/NBIB phone number listed, I have to fill out the FOIA form and mail it in.
What is this ‘hotline’ I keep hearing about people calling every month to get their status?

(724) 794-5612