Dead Man's Trail. K-9 Mystery Series

A frightened boy turns into a runaway murder witness, relying on only his bike and brains to evade the killers.  When Ricky Lopez skips school and bikes out to his boss's remote bungalow, he isn't worrying about anything except collecting his pay. Cleaning portables isn't a fun job, and he doesn't intend to let anyone cheat him out of his hard-earned cash.  But his life is upended when he witnesses a shocking murder and discovers the portables are used for trafficking illegal drugs.
Worse, the killers know his name, and what he's seen. Now he's on the run and hiding in the San Gabriel Mountains, with only his bike and a bag of stolen cocaine for company. Private investigator Nikki Drake and her K-9 Gunner aren't looking for a new case. But Ricky's distraught mother doesn't believe Ricky is playing hooky, and she needs help. Soon, Nikki and Gunner are deep in the California wilderness, desperate to find Ricky before the killers do. However, the gang leader has an inside track and trusting the wrong person can be deadly.
For both Ricky and Nikki.