The Supergun Mission (The Penetrator Book #21)
It started with the smuggling of Mexican "wetbacks" for slave labor in the U.S. They were brought to an island in Lake Texoma, north of Dallas, to work on a top-secret operation directed by H. H. Christiansen...and were forbidden to leave. But it wasn't until 25 Mexicans died in a mysterious tank truck fire that the Penetrator was called in. That's when this simple smuggling assignment turned into a national security threat.