Due to the location of Mitre Square, the City of London Police under Detective Inspector James McWilliam joined the murder enquiry alongside the Metropolitan Police who had been engaged in the previous murders.
Major Henry Smith, acting Commissioner of the City Police, claimed in his memoirs to have discovered bloodied water in a public sink in a court off Dorset Street, and as the water was slowly running out of the basin, he calculated that the Ripper had been there only moments before.