Yes, he was arrested immediately. The author retraced his journey to Sarajevo and researched his formative years.

Interesting fact: Princip died of tuberculosis in Terezin, where he was sentenced to 20 years (he was 19 when he committed the murder and the law stated he had to be 20 to be eligible to be executed). He was being treated by a doctor. A Jewish doctor. So a quarter century later, the doctor is sent to Terezin, now a concentration camp, and dies after being sent to Auschwitz.