How did Van Loo get hold of it?
Was he at the hotel that night?
Had he picked it up in the hall or passage when the servant dropped it?
When Hall handed him the paper and he first recognized it a fiendish thought, followed by a spasm of more fiendish rage, had sent the blood to his face.

But his crude common sense quickly dismissed that suggestion of his wife's complicity with Van Loo.

But had she seen him passing through the hotel that night, and had sought to draw from him some knowledge of his early intercourse with the child, and confessed everything, and even produced the paper with his signature as a proof of identity?
Women had been known to do such desperate things.

Perhaps she disbelieved her son's aversion to her, and was trying to sound Van Loo.

As for the forged words by Van Loo, and the use he had put them to, he cared little.