What supports a circumstantial reading of “wa-ʿalayhā ismun mamḥuwwun”?

Supplementary Practice 13: Attribution, Quotation and Evidential Restraint in Rhetorical Analysis

• Read it as a separate report unrelated in time to discovery
• Call wāw coordination solely from the position of ʿalayhā
• It describes the letter’s condition at discovery with a referring -hā
• Refer -hā to a new person rather than the preceding letter