In the novel After the Funeral, Oscar Lewis is an acquaintance of Michael Shane. Shane mentioned Lewis in establishing an alibi for the day that Cora Lansquenet was murdered. He said that he had a meeting with Lewis and one Mr Rosenheim to discuss some stage matters.
However, according to Mr Goby whom Poirot had asked to help do background checks on the key suspects, Shane's meeting did not take place. He had wired his contacts to tell them he could not make it and then had hired a car from Emeraldo Cars and driven into the country.