El asesino invisible

After a family dinner organized by the American millionaire Rodney Borger, seven diners were hospitalized with symptoms of alleged food poisoning. And although everyone soon recovered, decades later, the already dying tycoon has still not managed to get the strange episode out of his head. Before dictating his last wishes, he wants to be able to answer the question that has haunted him ever since: Which of his family members tried to kill him at that celebration? For this he will require the services of Professor Herman Brierly, a famous chemist and passionate about criminology. But just forty-eight hours after the reading of Borger's will, radio bulletins report that seven of his heirs have been poisoned in different cities in the states of New York and New Jersey, and four of them have died. Already. The most unsettling thing is that the victims seem to have collapsed almost simultaneously, despite living hundreds of kilometers apart from each other... What is the real purpose of what happened? Who is the invisible killer?