Amazon.com description: Product Description: BORDER ASSAULT 

The murder of several border patrol agents in a moonlight attack seems like an average Mexican cartel ambush…until the killers' weapons turn out to be U.S. military grade. There's a leak in the local army base, and it needs to be plugged before more ordnance trucks south—and more innocent lives are taken. Mack Bolan heads into the desert to investigate. 

But when an old ally is killed in a second assault, Bolan realizes he's underestimated the threat. Whoever is behind the attack is not only smuggling weapons into Mexico, but also building a private army. And the kingpin is intent on spreading his reign of terror into America. With an unofficial war about to break out on the border, he must plan a strategic strike to take down the empire and eliminate all its key players. And this time, for the Executioner, it's personal.