Vow of the Vigilante by Leighton Greene

Baxter Flynn is a wanted man in more ways than one.
He and Angelo Messina, ex-Underboss of the Morelli Family, have only strengthened their connection while they’ve been on the run, working toward their goal: find the one man who can clear their names.
But the law is always nipping at their heels, and for Bax—once an FBI agent—his underbelly life has never been completely comfortable.
Now Bax and Angelo have a solid tip on the whereabouts of their target, and with the help of the Castellani Family in Los Angeles, they might just pin him down…if they can get to him fast enough.
Because they’re not the only ones with an interest in the fugitive they’re chasing.
And all the while, one question grows larger in Bax’s mind: What happens after?
How can he and Angelo possibly make a life together that isn’t tainted by blood?