They sent more than 3, the first 3 were solved quickly, this was a 4th that was sent years later. I believe the only undeciphered message is the text at the end

They sent more than 3, the first 3 were solved quickly, this was a 4th that was sent years later. I believe the only undeciphered message is the text at the end of the 3rd cipher: ebeorietemethhpiti https://www.zodiacciphers.com/chronicle-letter.html https://www.zodiacciphers.com/chronicle-letter.html