The discrimination between counterfeited computer-generated documents has been one of the most challenging missions for forensic purposes. Forensic document examiners usually prefer using non-destructive techniques than a destructive one, but sometimes the latter technique can be the last decision for them. Our forensic laboratory has recently received a case involving many counterfeit one hundred Egyptian pounds 100 L.E produced using color laser printing machines, two of them having the same serial number and date of issue. The public Prosecution request the source of two counterfeited notes are they from the same source or not? We applied two approaches to answer this question, one of them spectroscopic techniques which include Fourier-Transform Infrared Spectroscopy (FTIR) as qualitative analysis combined with Scanning Electron Microscopy -Energy Dispersive X-Ray Spectroscopy (SEM-EDX) as quantitative analysis. We used the Video Spectral Comparator device (Regula 4307) as a physical technique. The result showed that the physical approach was superior for the classification and discrimination of color laser printing machines which encoding serial numbers to its brand source regardless of the toner type and the spectroscopic techniques were useful in discrimination of the color laser printing machines which not encoding serial number.