The Similarities of Thematic Progression in Zodiac Killer Letters

This study examines thematic progression in zodiac killer letters. This study aims to reveal the unknown killer whether it is personal killer or group killer. This study employs a descriptive qualitative method since it attempts to describe and analyze textual data accurately. The data of this study come from research publication article. After gathering the data, thematic progression theory proposed by Fries (2002) is employed to analyze the data. Findings show that constant theme is the type of thematic progression that is mostly used in the zodiac killer letters by 65.30%. However, some letters of zodiac killer contain a lot of similarities for instance they usually use constant theme and multiple theme but there is no linear theme. This study conclude that the similarities of thematic progression often occur in zodiac killer letters. It means that the zodiac killer letters are very possible written by one person. So it's a personal crime, not group killer