JUNKYARD DOGS by CRAIG JOHNSON

Junkyard Dogs - Craig Johnson
I wish Walt and Vic would figure out their relationship - well at least Walt because he's the one who seems to be putting the brakes on everything. 

Good story. I thought it was going to be the SPOILER [ old school teacher of Walt's (hide spoiler)] but no. Another surprise to me ending which has once again brought down my ego guessing these mysteries. Very good book/series.