An important aspect of the bloodstain pattern evaluation, resulting from a violent crime investigation, is the forensic biology analysis of the bloodstain evidence. This article examined four bloodstain pattern analysis cases in which DNA testing of the bloodstain evidence provided valuable information used for an accurate interpretation of the bloodstain patterns. The case studies presented illustrate the importance of the forensic biology analysis in interpreting bloodstain patterns. The data obtained from the forensic biology analysis must be incorporated into the final interpretation of the bloodstain pattern evidence. The DNA analysis demonstrated that the patterns examined were human blood, and could identify the origin of the blood.