Up in Flames by E.M. Leya

Rick Hardy knows fires. As an arson investigator, it’s his job to find the clues and hunt down the people who destroy with flames. When a serial arsonist goes after the homeless, he’s determined to put a stop to it.
Nate’s always been independent, seldom leaning on anyone for support, but when he finds himself the victim of the arsonist, he accepts Rick’s help, in return, assisting him in hunting down the man who is starting the fires and killing his friends.
It isn’t long before Rick and Nate realize that it’s not just the flames of the fires that are hot, but also the attraction between them. They might come from two different worlds, but the connection between them is smoldering.
As feelings grow between the two, so does the danger, and they must work together, protecting each other as they hunt down the man resolved to destroy the city and the homeless who live in it.
Determined to keep each other safe, Nate and Rick must find a way to think like the arsonist without putting either of them in the middle of the flames.