Authorities on Friday said a Readington couple found dead in a house fire were fatally shot in an apparent murder-suicide. Kathryn Shern, 70, and her husband, Charles Shern, 71, both died from gunshot wounds, according to the Hunterdon County Prosecutor’s Office, which released few other details about the investigation. In a statement, Prosecutor Renée Robeson characterized the deaths as “an apparent murder-suicide,” but did not say which person died by suicide or homicide. A spokesman for the prosecutor’s office did not immediately respond to a message seeking more information. “The investiga…