During the investigation of the Mondelo murder, police have turned their suspicion on business partner John Wayne Gretsky, finding questionable receipts on his desk (read the story). The students must determine if these receipts are legitimate business documents or evidence of a crime. To do this, students must determine objective criteria for handwriting analysis, and then apply these criteria when examining suspect receipts. After analyzing the handwriting, students will dissolve the ink from numbers on the suspect invoices. Then, using thin layer chromatography, they will create an ink profile for each of the samples taken from the receipt. From this information, students will determine if the same ink was used to fill out the entire form. Finally, by combining where different inks were used with what receipts are suspected of forgery, students can develop a complete theory of the suspected forgery. Supplies are included for up to 30 students working in six groups. As in all Lyle and Louise modules, this kit is geared to high school and undergraduate courses and is matched to National Science Education Standards. Kit includes 12 TLC plates, 6 development chambers, 6 bottles of solvent with droppers, 6 protractors, 100 microcaps, suspicious receipts with copies. Also includes fully illustrated teacher’s manual with technique background. It can be stored at room temperature.