Whipsaw — Robert L. Hecker

Recruited by the DEA, Brent Thomas goes undercover to investigate an ex-army buddy, Pat Frankie, who runs a boxing gym but who the DEA suspects is a drug dealer. Brent becomes an instructor in Frankie's gym. Frankie thinks he has the making of a champion and arranges fights for him. Brent, to everyone's surprise, wins the fights, eventually having a shot at the championship. Unfortunately, he also falls in love with Maria, Frankie's daughter. Then, entering the dangerous world of drug dealers, Brent must fight with his gun and his wits as well as his fists. An action-packed conclusion forces Brent into a traumatic choice: either a lie that will bring him Maria's love and a shot at the boxing title, or the truth that will cost him everything.