Final answer:
In 'The Picture of Dorian Gray,' Dorian Gray secures an alibi after killing Basil by spending time in an opium den, creating witnesses to his presence elsewhere.
Step-by-step explanation:
In Oscar Wilde's novel, The Picture of Dorian Gray, Dorian Gray provides himself with an alibi for Basil's death by going to an opium den after committing the deed.
There, he interacts with people who can later testify that they saw him, ensuring that he has an established presence away from the crime scene during the time Basil's body would be discovered. This alibi is a crucial part of the plot as it demonstrates Dorian's cunning and deceitful nature, and his ability to manipulate circumstances to protect himself.