Count to Ten by Karen Rose

"In all his years in the Chicago Fire Department, Lieutenant Reed Solliday has never experienced anything like this recent outbreak of house fires -- devastating, vicious, and in one case, homicidal. He has another problem: his new partner, Detective Mia Mitchell. She's brash, bossy, and taking the case in a direction he never imagined.

Mia's instincts tell her the arsonist is making this personal. And as the infernos become more deadly, one look at the victims' tortured faces convinces her and Reed that they must work closer to catch the killer. With each new blaze, the villain ups the ante, setting firetraps for the people Reed and Mia love. The truth is almost too hot to handle: This monster's desire for death and destruction is unquenchable . . . and for Mia he's started the countdown to an early grave."