刑案現場勘察人員在刑案發生後，進入現場執行勘察及採證，並以刑案現場勘察報告呈現現場情況、採證記錄及勘察後對案情提出的分析研判及結論，成為偵查及起訴的重要證據之一。本文首先簡述勘察人員在刑案現場的作為以及勘察報告的內容，勘察報告中不論是在現場勘察及採證的過程，或是報告撰寫的描述，都不僅為機械性的記錄，其中許多部分涉及鑑識人員的主觀判斷詮釋以及專業知識技術呈現。因此，勘察報告的內容實兼具有證人的陳述及鑑定人的意見，應將勘察人員定位為兼具鑑定證人與鑑定人身份之人。在確立勘察人員的定位後，因鑑定證人的證人地位具不可替代性，應適用證人的調查程序，現場勘察報告為傳聞證據，除非獲得合意否則不具備證據能力，因此現場勘察人員必須出庭作證。比較美國法專家證人的調查程序，並肯認對質詰問權為我國憲法保障的權利，勘察人員不論是提出證人證詞或鑑定人意見皆為被告對質詰問權的對象，肯定現場勘察報告應以言詞提出為原則，並出庭接受交互詰問。此外，法院應實質審查勘察報告中所提出之鑑定意見，確保現場勘察之證詞符合專業上的可信性，故借鏡美國證據法上專家證人的資格審查標準，作為現場勘察人員所出具鑑定意見，是否具有可信性的判斷標準。最後，提出在強調鑑定人出庭義務下，造成鑑定及現場勘察實務衝擊的可能解決辦法，供實務界及立法者參考。

When a crime occurs, crime scene investigators (CSIs) arrive at the scene, document the scene, collect evidence, and then transfer it to the crime lab. The crime scene investigation report contains the record of what CSIs did at the scene and the crime analysis is based on what is the observation and evidence. This paper would then become an essential piece of evidence in the following criminal procedure. This article introduces what CSI does at the crime scene, steps to complete a report, and how a conclusion is developed from its content. This paper categorizes crime scene investigators as expert witnesses instead of just witnesses. Due to the irreplaceable characteristic of CSIs, provisions relating to witnesses shall be applied to the examination of CSIs. Because the crime scene investigation report is the hearsay evidences, unless the party consents to its admissibility as evidence in the trial, the crime scene investigation report should not be admitted as evidence. This paper analyzes the cases regarding expert witnesses and the Confrontation Clause in the U.S. This article concludes that crime scene investigators should make reports verbally in court and be examined by the accused, instead of submitting the report merely in writing. Because there is no clear rule to verify the credibility of expert witnesses in Taiwan, this paper refers to the U.S. Evidence Rules’ standard to examine the opinion of CSI in the report. Finally, this article offers forensic scientists and legislators recommendations to resolve the practical issues that may occur when CSIs are required to testify in court.