Shadow of the Knife (Celaeno, Book 1)

Militia rookie Ellen Mittal is well aware that the world cannot be reduced to simple questions of black and white, but she has no idea of just how complex and dangerous her life is about to become. The most vicious gang in the Homelands, led by the infamous Butcher, is extending its operations to Roadsend. By her oath as a member of the Militia, Ellen is sworn to uphold the rule of law, no matter what the cost to herself. But as the body count starts to rise, Ellen finds her task made all the harder by a wall of silence from ordinary citizens, a commanding officer with her head in the sand, and the attentions of an attractive young farmer who is probably not who she claims to be. Ellen must work out who to trust, because if she gets it wrong she might easily lose her heart, or her life.