Chris Bradford 
Bodyguard: Target (Book 4) 

A prequel and new entry point in the bestselling Bodyguard series.
FAME MAKES FOR AN EASY TARGET.
Ash Wild is the most successful teen rockstar in history. Millions of fans adore him. But one fanatic wants him dead.
Surf champion and top bodyguard recruit Charley Hunter is assigned to protect the superstar on his sell-out US tour. But Ash isn“t pleased to discover his new bodyguard is a girl.
Faced with a growing number of death threats, several suspicious accidents and an unruly rockstar, Charley has her work cut out keeping Ash alive on the tour. How will she spot a killer in a crowd of 50, 000 screaming fans?