The Prodigal Spy by Joseph Kanon
It is 1950 and communists are being hunted across America. When Walter Kotlar is accused of being a spy by the House Un-American Activities Committee, his young son Nick destroys a piece of evidence only he knows about. But before the hearing can conclude, Walter flees the country, leaving behind his family...and a key witness lying dead, apparently having committed suicide. Nineteen years later, Nick gets a second chance to discover the truth when a beautiful journalist brings a message from his long-lost father, and Nick follows her into Soviet-occupied Prague for a painful reunion and the discovery of a secret that changes everything. To unravel the lies Nick must return to where it all began and expose the one person who knew the truth - and who watched his family's destruction. Trust no one in this compelling, surprising thriller from the author of Leaving Berlin and The Good German.