What does Mr. Cuss tell people? What fact does Cuss quickly catch on to?

Mr. Cuss catches onto the fact that Marvel was carrying the package.

And suddenly the parlour door was opened, and Mr. Cuss appeared, and without glancing at her rushed at once down the steps toward the corner. "Hold him!" he cried. "Don't let him drop that parcel."

He knew nothing of the existence of Marvel. For the Invisible Man had handed over the books and bundle in the yard. The face of Mr. Cuss was angry and resolute, but his costume was defective, a sort of limp white kilt that could only have passed muster in Greece. "Hold him!" he bawled. "He's got my trousers! And every stitch of the Vicar's clothes!"