Alan Campbell had shot himself one night in his laboratory, but had not revealed the secret that he had been forced to
know…his suicide had been his own act. He had chosen to do it. It was nothing to him.

– Oscar Wilde

The Picture of Dorian Gray, Chapter 20. Dorian’s selfishness leads to the scientist Campbell’s death. Having blackmailed him into disposing of Basil Hallward’s body after Dorian murdered Hallward, the scientist shoots himself in his laboratory "without revealing the secret that he had been forced to know." But Dorian typically refuses to accept any responsibility for the suicide – as he did Sibyl’s. There is no remorse from Dorian and so there will be no redemption for him.