Sit Down and Rest

Holmes booked a carriage, and the three hurried over to the chemical plant.

"Conspirator?"

Gregson was surprised.

"Didn't you say that this was a crime of passion? The suspect obviously did not plan. The reason why he killed Molly was that she resisted fiercely. It frustrated the killer. And as you said earlier, there were only two people left in the textile factory."

"This is the last key that complements my reasoning, and it is also the most important key," Sherlock deduced with surety in his voice.