From 2 of 3 ‘Bates had to die’ notes
“Xi (uppercase Ξ, lowercase ξ; Greek: ξι) is the 14th letter of the
Greek alphabet. It is pronounced [ksi] in Modern Greek, and generally /zaɪ/ or /saɪ/ in English. In the system of Greek numerals, it has a value of 60. Xi was derived from the Phoenician letter samekh
Xi is not to be confused with the letter chi, which gave its form to the Latin letter X.” Wikipedia
The signature could be a combination of the 2 Greek letters xi and lambda = soft x with L for Xenophon Lusby. Xenophon was of Greek origin (Antonaides/Anthony?) and a graduate of Harvard where he most likely would have used the Greek alphabet. The Gematria of the 888 in his 32 letter cipher shows an awareness of the ancient Greek roots of English as well. Lusby was Xenophon’s middle name. I have to thank Richard Grinell and his Zodiac Ciphers website for the Gematria links. It seems like the signature is either an addition by Xen/ fon the accomplice to the crude handwriting of the note, or,
Was Xenophon Lusby Anthony the Zodiac, beginning to write with his left hand to disguise his hand, but signing more confidently with his right?