] I began to suspect Parrish around the time that he showed up with scratches on his face.

We believed what the writer wanted us to believe. Even though we cannot fathom why he fell so quickly and completely for Caroline, the writer's description of his kindness and patience towards her convinced us.

If she had decided to drop a few lines that showed us his evil side, i.e. that Lizzy caught a ruthless glint in his eye, or overheard him giving Caroline orders, we would have not been as suprised.