I Will Find You by Harlan Coben
During a rare prison visit, David Burroughs’ sister tells him that she spotted Burroughs’ young son in a friend’s vacation photos. As Burroughs is serving time for the murder of said son, this sighting seems highly unlikely. But since Burroughs knows he did not commit the crime, he is determined to discover the truth. This means breaking out of a maximum-security prison to track down a flimsy lead, but hey, fiction!
The denouement is a bit far-fetched, but the novel is reliably readable. Coben never disappoints.