The chemical analysis revealed that the seizures capsules labeled as Desobesi-M1 (fenproporex 25 mg), actually contained the active pharmaceutical ingrediente (API) sibutramine. The amount of this active pharmaceutical ingrediente ranged from 1/3 to 2 times the amount of drug found in commercial product, may reach twice the recommended daily dose. Multivariate analysis with application of principal component analysis on data from spectroscopy attenuated total reflectance Fourier transform infrared classified the samples according to their similarities, indicating that two seizures had common origin. This study represents the first step in the elucidation of falsification of amphetamine-type stimulants in Brazil. Considering the forensic intelligence these information are valuable in order to develop and establish a database that enables correlate samples from different locations and/or suppliers and to map the profile and trends of trafficking.