Jack the Ripper
In 1885 his father died. A couple of years afterwards, his mother was institutionalized for depression and paranoid delusions. His family had a very pronounced history of depression and suicide.
Despite the tragedies in his life and a genetic propensity towards depression, Druitt prospered financially and socially in the 1880s. He was very secure financially and had inherited money from both parents. He had a very good teaching position and had become very active in many sports. The social circles in which he moved were very respectable.
However, all was not as well as it seemed, because his body was found floating in the Thames River at the end of December 1888, where it had been immersed for weeks. He had been dismissed from his teaching position, probably around the end of November. He left a suicide note, which was found by his brother: "Since Friday I felt I was going to be like mother, and the best thing for me was to die."
There does not seem to be any real evidence as to why Macnaghten considered him a serious suspect. The only suggestion is that cryptic message of Macnaghten's: "from private information I have little doubt but that his own family believed him to have been the murderer." Macnaghten claimed he had destroyed all of the relevant documents, so the answer may never be known. Thus far, no one has been able to come up with any credible evidence to suggest that Druitt was even a violent person or "sexually insane," as Macnaghten stated, let alone Jack the Ripper. Chief Inspector Abberline, who was the most knowledgeable person in the police department about the Ripper murders, did not consider Druitt a suspect.
Philip Sugden compares Druitt to the eyewitness accounts of the Ripper. While Druitt is within right age category and wore a moustache, his build is too slight to have been described by any of the eyewitnesses. The person they saw was anywhere from medium build to stout. Also, Druitt hardly looked foreign or Jewish. He did not live in nor frequent the East End, and there was no train service between his lodgings in Blackheath and London that would allow him to commit the murders and return home. Plus, in the death of Annie Chapman at 5:30 a.m., it would have been very unlikely that Druitt could have murdered her, cleaned himself up and caught a train back to Blackheath in time for a cricket game he played at 11:30 a.m.
In summary, Macnaghten was no fool and he certainly had access to all Ripper suspect records, many of which no longer exist. So, there may have been some important evidence about Druitt to support his suspicion. However, without that evidence, it is difficult to see why Druitt is a suspect. One can explain his suicide at the end of November as the tragic end of a losing fight with hereditary depression. With so many people in his family afflicted with mental illness, he may have recognized the symptoms in himself and committed suicide.