The primary goal of this study was to present the summative evaluation findings of an initial implementation to investigate the impact, effectiveness and perceived benefits of the Electronic Performance Support System (EPSS) on the performance of Crime Scene Investigation (CSI) officers in Turkey. A sequential explanatory strategy as a procedure of mixed method design was used to collect data through a survey, interviews, and computer logs. While 191 CSI officers participated in the quantitative part of the study, the researchers also conducted interviews with 12 officers. Data was analyzed by using descriptive statistics and content analysis. The results showed that intrinsic support made a major contribution to officers' performance with positive reactions. It revealed also that generating reports and establishing standardization were one of the main factors providing impacts on society. This study provides a viable application of Kirkpatrick's Four Levels of Evaluation model for the CSI Unit; however, the model's extended adaptations should also be carried out in different workplace settings for further studies.