Crucial Intercept (Executioner #386) by Don Pendleton
A series of high-profile shootings in Virginia exposes a deadly scavenger hunt with numerous factions competing for the prize. An ex-CIA cryptologist who created an unbreakable code has unwittingly been sold out to the terrorist group who can get to him first. Before any more innocent lives are lost, Mack Bolan must intercept the human bounty and keep the code from falling into enemy hands.
With several fully equipped foreign black ops groups tracking his every move and willing to die for their cause, Bolan is running out of time, ammunition and options. He has only one choiceturn the war back on the terrorists. A single American citizen may hold the key to military superiority, but there is only one soldier who can defend itthe Executioner.