Bride of Frankenstein : One Loophole I Just Noticed

When Dr Pretorius first comes to Dr Frankenstein with the proposition to make a bride for the monster, they're all supposed to think he was dead at that moment.

The only one who knew he was alive at that time was Minnie who no one believed when she told them.

Why was Dr. Frankenstein almost agreeing to do so when he didn't know yet that the monster was still alive?

When Pretorius was speaking with Henry in his bedchamber, he said ...and with your creature still at large in the countryside.... There's no indication that Minnie mentioned anything to Pretorius about the creature, and he had no other interaction with Frankenstein's staff, so presumably rumors had reached him in town through more credible sources. Since Henry didn't seem surprised when Pretorius told him the creature was still at large, perhaps the same rumors had already reached the Frankenstein household - or maybe Henry believed Minnie's own account, despite her tendency for hysterics.