I have finally pinpointed what I find disconcerting about these books. It's the split narration! There are some chapters in a third-person omniscient style, where the author follows the killer, or one of Lindsay's friends, and then other chapters are narrated in first person by Lindsay herself. After reading the first book, I half expected the second to have one of the other ladies as the first-person narrator. Unfortunately, all these books follow Lindsay.
This third book was a bit different in that up until the fourth killing, I was partially rooting for the bad guys---going to war with corrupt CEOs and unethical leaders of health care organizations. I don't actually think those people should be killed, but I do think they may need to shape up.
The ending was mildly surprising, although one can expect that the person responsible for the deaths will always be someone slightly different than expected when reading a novel by Patterson.
Overall, a compelling read and worth the day and a half it took me to read it. (Not that all I did was read this book for the past day and a half, I did other stuff too...like go to work.)