Michael Underwood 
Menaces, Menaces [EPUB ebook] 

The first ’menaces’ brought Herbert Sipson, professional blackmailer, to the dock, charged with having demanded 10, 000 from a bingo company under threat of bombing their premises. The second is a demand for 100, 000 from the Swallow Sugar Corporation under threat of introducing ground glass into some of its bags of sugar on the supermarket shelves. It, too, bears all the hallmarks of a Herbert Sipson scheme. But it arrives on the opening day of Herbert’s trial and he has been locked up in prison. How can he be responsible?