Why is Cottard’s crime never specifically revealed? Does the nature of that crime make a difference?
Knowing the details of Cottard's past life might provide additional insight into his character. However, the nature of his crime matters less than the influence it has on his current actions. His attempted suicide and his subsequent fear of arrest demonstrate the degree to which his crime continues to haunt him. Because he lives in a constant state of fear, he is able to interact with others only when they, too, fear the spreading plague. The way he takes advantage of others' misfortunes to sell contraband suggests that he has a history of swindling. In the end, his instability and erratic actions in response to his criminal past, not the crime itself, lead to his arrest.