Spotting fake documents by verifying against the source
A convincing forged PAN card or RC will pass a human eyeball. It will not pass a lookup against the issuing database. That is the whole point.
Why visual checks fail
Template forgeries are cheap and good. Holograms, fonts and layouts are all reproducible. A reviewer comparing a photo to a reference is guessing. The only reliable question is: does this number exist in the source, and does the data attached to it match what the person claims?
The mismatch is the signal
Fraudsters often use a real number that belongs to someone else. The number verifies, but the name does not match the applicant. Your check must compare the returned identity to the claimed identity, not just confirm the number is real.
Layer the checks
One check is a data point. PAN name plus Aadhaar-linked name plus bank account name all agreeing is a strong identity assertion. Any one disagreeing is a review trigger. Fraud rings are good at faking one document, not three that have to be internally consistent.