自電腦於1946 年發明以來，其應用的領域已從一開始的科學計算、資料處理不斷的擴張。然而，隨著電腦與網路的普及，各類之電腦網路犯罪卻也因此開始滋生。惟此類牽涉到電腦或網路之犯罪，因電腦及其相關電子設備本身之特性，故相較於傳統犯罪而言，較不容易偵查，執法上亦因此面臨著許多的困難。在美國，早期針對搜索扣押與犯罪有關之電腦檔案等數位證據時，司法解釋上曾出現過許多爭議。惟近年來，美國法院對於電腦犯罪案件中數位證據之搜索與扣押所可能會牽涉到的幾點重要爭議，已逐漸形成共識。本文之目的，即在於透過美國近年來有關數位證據即時偵查之法制、搜索扣押以及保存數位證據之相關規範及實務見解，來了解數位證據之取得與保全於法制上應遵守那些規範？當相關規範之適用出現疑問或困難時，美國法院又係如何解決數位證據在刑事訴訟中所面臨之種種程序或法制上之考驗？藉此作為未來國內後續相關研究以及執法實務上之參考。

Over the past several decades, computers have become a principle means for storing personal, financial, and other information for large numbers of people. The significance of computers as a source of information suggests that access to computer records will become increasingly important in law enforcement. However, computerized records have several unique characteristics that are different from the physical evidence, and those unique characteristics have increased the difficulty in criminal activity’s investigation and prosecution.In response, the Department of Justice in the United States have created numerous programs and deployed new technologies to aid in the investigation and prosecution of
computer crime. Department of Justice’s efforts to combat crimes that involved computer are centralized in its Computer Crime and Intellectual Property Section. The Section has published Prosecuting Computer Crimes” and “Searching and Seizing Computers and Obtaining Electronic Evidence in Criminal Investigations” manuals to examine the federal laws that relate to computer crimes. In addition, courts and legal academics have been responding to this trend with increasing regularity, struggling to apply Fourth Amendment jurisprudence to the new contexts.Therefore, this article will examine legal issues related to search and seizure of computers and the preservation of computerized evidence.