If there is no evidence in the claim file indicating the reason
for the late filing, send the claimant and the claimant's representative
a letter requesting an explanation. Place a copy of the communication
sent to the claimant in the claim file as an exhibit.
If the file is paper, ask the servicing field office to forward any
pertinent information in its files, e.g., any letter or communication
from the claimant, representative, or the claimant's family, a copy of
any records containing information regarding pertinent contacts, etc. If
the case is electronic, look in the electronic claim(s) file for any new
pertinent information that may have been entered by another office.