Series numeration from goodreads.com

"Two fiery deaths have young lawyer Daniel Pitt and his scientist friend Miriam fford Croft racing to solve a forensic crisis in an explosive novel from the New York Times bestselling author of Triple Jeopardy. When a desperate woman comes to Daniel seeking a lawyer for her boyfriend, Rob Adwell, Daniel is convinced of the young man's innocence. Adwell has been accused of murder and setting a fire to conceal the body, but Daniel is sure that science can absolve him--and the brilliant Miriam fford Croft is the best scientist Daniel knows. Working together with Miriam, Daniel reveals Adwell's innocence by showing that an accidental fire caused the victim's death. But it's not long before Adwell is killed in the same fiery fashion. If these deaths are, in fact, murders, what could Miriam have missed? As the evidence begins to contradict itself, Adwell's girlfriend comes into question--and so do the methods Miriam has been using. Soon Miriam's career hangs in the balance, and what started as an accidental fire seems to be part of a larger plot of revenge, with victims accumulating in its wake. Now Miriam and Daniel must uncover who or what is stoking these recurring flames--before they, too, find themselves burned"--