First suspected: 1894, first suggested in the Macnaghten Memoranda.
Reasons for suspicion: According to Anderson and Swanson, identified by a witness as the Ripper, but no charges were brought against him due to the witness's reluctance to testify against "a fellow Jew." Known to have been insane.
Problems with candidacy: Discrepancies between Aaron Kosminski and the "Kosminski" described by Anderson/Swanson. Not known to have had violent tendencies.