Gus Jackson is a new internal auditor for a newly acquired subsidiary ABC company, working with Jane Ramon for auditing year$-$end AP function.

A written comment on some AP checks that lack of complete endorsement by the payees. Especially dual payees and endorsement of each payee is required.

Finding $5$ checks with the same handwriting but names are different.

All have been cashed at the same convenience store less than $5$ miles from office, though one mailing address was $200$ miles away. No supporting document is found.

Investigation showed that $\frac{95}{60},000$ paid checks has been cashed in above store.

Suspicion of "fictious payment to real payees". Use "affidavits of forgery" to narrow down $7$ suspects to commit the fraud. Use "personnel spreadsheet file" to detail each suspect.

Hank Duckworth, AP manager, used to be Gus' former big $4$ firm client, was confirmed perpetrator.

Former residence was near the store to cash in$.$

He pled guilty and received probation sentence in return of full restitution.

Case $1$: internal audit on year$-$end AP Gus Jackson$/$Jane Ramon$/$Hank Duckworth $($Ch$1-$Casel$-2/4)$

What clues cause Jane to suspect that fraud was involved?