Paul Temple and the Jonathan Mystery

The case involves the Fergusons, who Paul and Steve meet while on the way home from New York. They are flying to England to visit their son Richard, a student at Oxford University. But at the airport, there is shocking news: Richard has been murdered, found shot dead in his room. The only clues are a postcard from Harrogate signed 'Jonathan', and Richard's missing gold signet ring.But who is Jonathan, and what is his connection to the dead man? It is up to Paul to find the answer...