Here's why:
* Fictional vs. Real: Sherlock Holmes is a fictional character created by Sir Arthur Conan Doyle. Jack the Ripper was a real-life serial killer who terrorized London in 1888.
* Timeline: The crimes attributed to Jack the Ripper occurred in 1888. Sherlock Holmes's first appearance in print was in 1887 in "A Study in Scarlet."
* No Canonical Connection: There are no stories in the Sherlock Holmes canon that mention Jack the Ripper.
Some authors have written fictional works featuring Sherlock Holmes investigating Jack the Ripper, but these are not considered canon and are not recognized by the Sherlock Holmes estate.
The mystery of Jack the Ripper's identity remains unsolved, and while many theories have been proposed, there is no definitive evidence to link the killer to any specific person.