Beyond This Place — A.J. Cronin

Paul Mathry, a student about to graduate and embark upon a teaching career, finds out that his father was convicted for murder, a secret that his mother had hidden from him since his childhood.
Driven by an intense desire to see his father, Paul sets out to visit him in prison, only to find out that visitors are never allowed there.
From there, he meets the primary witnesses in the case that convicted his father, not all of whom are supportive to Paul's cause. He encounters several dead ends but he persists, with the help of a store girl named Lena and a news reporter.
His persistent campaign finally bears fruit. Rees Mathry, Paul's father, goes on appeal...