Patricia Cornwell's first few books were pretty good. I read each one as it came out. Then came this one, a major disappointment, and Southern Cross, which stinks so bad it makes skunks smell good in comparison.

Unnatural Exposure is part of the Dr. Kay Scarpetta series. Scarpetta is a fictional Virginia medical examiner.

When she's good, Cornwell can write some great, engaging, scary stories. But when's she bad, well, it's not pretty.

For most of this book, she held my attention. Some of that momentum was kept up, though, by referring to characters and plot lines from the earlier books — as well as putting off some stories for the next one.

The plot itself is good: a serial killer is hunting and killing selected people by releasing a mutated version of smallpox. The killer taunts her by sending electronic mail through America On-Line so the FBI tries to trip the killer up by having the real doctor and "deaddoc," the suspect's on-line name, meet in a chat room so they can trace the call.

While the character of Scarpetta is interesting — it's not everyday that a medical examiner is the heroine — she is getting so hardened on the world (shades of Cornwell's famously guarded personality?) that she is becoming gradually less interesting.

More interesting is her niece, Lucy, a computer expert working for the FBI who is being hassled because she is lesbian. After reading the book, and feeling the desire to throw it against the wall when the suspect was revealed, I checked to see what other readers thought of it by looking at reviews at Amazon.

Sure enough, most had the same opinion: this was a book that seemed rushed and is one of her weaker efforts. Several suggested focusing a story around Lucy instead of Kay, which is a pretty good idea.

Overall, the characters in her book are becoming less interesting and I'm questioning whether I'll read another Cornwell book.