Lawrence Cavendish is Emily Inglethorp’s stepson and John Cavendish’s brother. Unlike John, he’s shy and reserved, which sometimes makes him hard to read. For this reason, he comes under suspicion after Emily’s murder, especially because he’s the only person who insists on the theory that she could have died of natural causes. Poirot finds this suggestion strange, considering that Lawrence originally trained to be a doctor but then decided to become a poet. Given his medical education, Lawrence should be perfectly capable of recognizing the effects of the strychnine poison on his stepmother, and yet he insists that she simply died of heart failure. What’s more, he made a point of visiting Cynthia Murdock at the dispensary (where she mixes medicine) the day before the murder, and while he was there, he even opened a cupboard containing strychnine. However, Poirot later reveals that Lawrence’s suspicious behavior has nothing to do with murdering his stepmother. Rather, Lawrence is hiding something completely different: namely, the fact that he’s in love with Cynthia and doesn’t want her to get in trouble. Nobody knows he has feelings for Cynthia, including Cynthia herself, but this doesn’t stop him from trying to shield her from harm. When he and the others first entered Emily Inglethorp’s bedroom on the night of the murder, he was shocked to see that the door leading to Cynthia’s bedroom had been unbolted. He therefore thought she was the murderer, and he didn’t want anyone to find out, so he tried to convince everyone that Emily wasn’t poisoned to death. After Poirot reveals Alfred and Evelyn to be the real murderers, Lawrence and Cynthia finally start a romantic relationship.