Sample Blood:
Sample blood plays a crucial role in forensic investigations, acting as primary evidence that can offer vital insights into the specifics of a crime. This type of blood is acquired from various sources, including bloodstains found at the crime scene, blood samples collected during victim autopsies, or blood drawn from suspects for comparison purposes. Once collected, the sample blood undergoes thorough analysis in order to extract pertinent information that can assist investigators in solving the case.

The primary objective of analysing sample blood is to establish connections and identify individuals involved in the crime. Through DNA analysis, a unique genetic profile can be obtained from the sample blood, serving as a powerful identifier that allows forensic experts to match bloodstains to specific individuals with a high level of accuracy. By comparing these DNA profiles to those of known suspects or individuals in forensic databases, investigators can establish connections, identify potential perpetrators, and build a strong evidentiary case.

Moreover, the analysis of sample blood can aid in determining the cause of injury or death, providing insight into the circumstances surrounding the victim's demise. Forensic pathologists thoroughly examine blood samples for the presence of drugs, toxins, or other substances that may have played a role in the fatal outcome. By identifying these factors, investigators can uncover crucial details about the sequence of events leading up to the crime, such as the use of weapons, the administration of harmful substances, or the existence of underlying medical conditions.

In addition to identifying suspects and determining the cause of death, the examination of blood samples is also crucial for reconstructing the sequence of events related to the crime. The presence of bloodstains at the crime scene or on the victim's body can yield valuable insights into the dynamics of the altercation, the movements of those involved, and the method of the crime. By carefully studying the distribution, pattern, and characteristics of bloodstains, forensic experts can piece together a timeline of events, identify potential weapons or tools used, and establish the series of actions that led to the crime.

Overall, the analysis of sample blood is a fundamental component of forensic investigations, providing crucial information that can help unravel the mysteries surrounding a crime. Through meticulous examination and interpretation, forensic experts can use sample blood to establish connections between individuals, determine the cause of death or injury, and reconstruct the events of the crime, ultimately aiding in the pursuit of justice and the resolution of criminal cases.

Control Blood:
Control blood serves as a critical point of reference in forensic investigations, serving as a known standard against which blood samples collected from crime scenes or suspects can be compared. Unlike sample blood, which is directly linked to the case being investigated, control blood is obtained from individuals who have no direct involvement in the crime. This ensures that any similarities or differences observed between control blood and sample blood are not influenced by the specific circumstances of the case, thereby increasing the precision and dependability of forensic analyses.

The main purpose of control blood is to establish a baseline for comparison, particularly in DNA profiling and blood typing analyses. By comparing the DNA profile or blood type of control blood with that of sample blood, forensic experts can determine whether bloodstains found at the crime scene belong to a suspect, victim, or another individual. This comparison helps identify the source of bloodstains, detect potential sources of contamination, and distinguish between relevant and irrelevant evidence.

Additionally, control blood plays a crucial role in validating the accuracy and reliability of forensic testing procedures. Before analysing sample blood, forensic laboratories often subject control blood to the same testing protocols to ensure the consistency and reproducibility of results. This quality control measure helps guarantee that forensic analyses produce dependable and accurate findings, thus strengthening the credibility of forensic evidence presented in court.

Additionally, control blood plays a crucial role in identifying and removing possible sources of contamination in forensic examinations. Through comparison of DNA profiles or blood types between control blood and sample blood, forensic professionals are able to detect any discrepancies or abnormalities that may indicate contamination from environmental factors, equipment, or individuals. This allows for proper measures to be taken in forensic labs to prevent contamination and maintain the integrity of evidence.

As a whole, control blood is an essential tool in forensic investigations, increasing the precision, dependability, and validity of analyses. By establishing a known benchmark for comparison, control blood aids forensic experts in determining the origin of bloodstains, verifying the accuracy of testing procedures, and detecting potential contamination sources. Ultimately, control blood is crucial in ensuring that forensic evidence meets the highest scientific standards, strengthening its admissibility and relevance in legal proceedings.

Written By: Md.Imran Wahab, IPS, IGP, Provisioning, West Bengal
Email: [email protected], Ph no: 9836576565