The Zodiac killer used quotations from the Mikado by Gilbert and Sullivan on his ‘Little List’ Letter postmarked July 26th 1970 and on the Exorcist Letter when he recited ‘Tit Willow’. These were the only two pieces of correspondence where he made reference to the Mikado. But there could be a third present on the Halloween Card, when he writes ‘peek-a-boo’ around the knothole in the tree.
Zodiac was artful in misdirection and often mocked the police and authorities using words such Blue Meanies, taken from The Beatles Yellow Submarine and possibly took the name Zodiac from Charlie Chan’s Treasure Island, often appearing to glean material from other sources, such as the Mikado.
But why did he place peek-a-boo around the knothole in the tree.
The original Mikado debuted at the Savoy Theatre in London, England on March 14th 1885.
The answer could be in the form of a parody of the Mikado, a ‘send up’ of the characters in the Gilbert and Sullivan opera, published in 1888, the date of the ‘Jack the Ripper’ murders and called ‘The Capitalist’ or ‘The City of Fort Worth, The Texas Mikado’ by Ed J Smith.
Peek-a-Boo is one of the characters from this stage parody and could possibly be the Zodiac’s third reference to the Mikado, contained within the Halloween Card and another example of the killers subtlety of laying misdirection within his numerous cards and letters.