Criminal Investigation: Importance of Semen

Detection of semen in forensic cases mostly sexual assault or misuse in critical for evidence getting together. An ability to be taken about the forensic light source, which gives out wavelength from 430 nm to 700 nm UV to VIS. and apparatus for making liquid clean were used. The very high-intensity light source sensed semen in darkness and daylight using wavelengths between 415 nm to 490 nm. ABO blood grouping careful was is the eldest careful way used in forensic biology for grouping purposes. But nowadays, DNA fingerprinting is an advanced technique used to solve crimes like group rape. Even though in this case simplest and most old ABO blood grouping careful way helped to solve a group rape case. In the present case, one attacked person was 5 years old girl who had sex by force by a person. Screening the semen color-damaged spots using able to be taken about the forensic light source and primary testing of semen color-damaged spots from different places on victims’ underclothes was done. ABO blood grouping of each selected semen color damaged spots was done by the absorption-elution careful way. Those selected color-damaged spots showed blood group which matched with the accused person blood group. Thus, the accused person was declared guilty of a criminal offense in this completely hate-causing crime.


As the number of rape cases is increasing day by day there is a need for detection of sperm and semen even if present in small quantity no matter how old the color-damaged spots are we have to detect these color-damaged spots through details. For detection of sperm and semen are the most dependable marker for the investigation in cases of rape, sodomy, bestiality, sexual put to death, and so on. Detection of sperm is an important factor in making certain sexual Assaults. This article provides a brief know how the need for detection of sperms and semen different methods applied for the detection with special making a point of on the current chemical tests with accurate procedures for giving effect to these tests.

In a forensic observation, semen can be sensed by the existence of the enzyme acid Phosphatase because this enzyme is present elsewhere in the body, however, the test is not absolute proof of the existence of semen on clothing or in material got over disease in a case of had feeling it was probable sexual assault. But the detection of acid phosphatase is powerful circumstantial evidence and points to that further efforts should be made to investigate the possible state of that semen is present. 

Semen Contains the Following

1. Spermatozoa (10%) 

2. Seminal plasma (90%) 

3.Epithelial cell (<1%) 

The spermatozoa are produced in the testis by the process of spermatogenesis. Spermatozoa have within lipid proteins like protamine and histone and so on and enzymes like dehydrogenases and Transaminases. The total length of spermatozoa is about 50 it from of head and tail. The head is flat, oval formed 4.6×2.6×1.6 in length distance from side to side thickness. The Nucleus is living in a major part of the head. The tail part is responsible for the motion of sperm. The seminal plasma is a mixture of secretion derived from the male accessory reproductive organs like epididymis, seminal vesicles, the prostate, vasa- deferential, Bulbourethral, and urethral glands. The seminal plasma has in it citric acid, ascorbic acid, lactic acid, Fructose, potassium, choline phosphatase, proteases, free amino acids, Ergothioneine zinc, calcium, spermine lipids, enzymes like Fibrinogenase, distance, acid, and alkaline, phosphatase glycosidases, A and b Glucosidases, mannoxidases B Givcouridases. 

The seeing who the person is of semen is of great value in Medicolegal practice like put for supposed rape cases or sexual assault. The primary purpose of semen forensic analysis is to sample and look at marks and other biological material taken from the attackers the sufferer or color-damaged spots discovered on clothes and or other evidence at the crime place. In cases of sexual assault 2 steps are needed: give the position of the stain and prove its identity. A semen analysis can also help in successfully connecting semen to a person likely to wrongdoing through DNA making common with a group. 

Presumption Tests for Semen

1. Visual and alternate light source ALS semen can be sensed with a naked eye in clothing and under-clothes or through the case of ALS such as ultraviolet light. 

2. Acid phosphatase (AP) test the male prostate gland produces and secrets a high amount of acid phosphatase (AP), an enzyme in the semen using standard chemical reactions, laboratories can analyze a given stain for the existence of this enzyme. In the existence of certain color- damaged spots, AP will produce a dark red-blue mixed color in less than a minute. 

3. Prostate-specific antigen (PSA) also experienced as PSA or P30 can be sensed in semen. PSA is produced in high amounts by the male prostate gland but can also be discovered in very small amounts in the fiscal matter and chest milk. 

Confirmatory Tests for Semen

1. The Christmas tree stain is a positive seeing who a person is of sperm units 2 reagents are used one after another to produce this different stain: picroindigocarmine color-damaged spots and nuclear fast red. The first stain color-damaged spots the neck and tail of the sperm cells in green and blue since the latter one color-damaged spots the sperm head and Acrosomal cap with red and pink separately. 

2. RSIP- semen Strip test: This test provides sensitivity and specificity to human semen. Like pregnancy test long (thin) bit, the RSID- semen text takes to be the same the existence of the seminal vesicle specific antigen. This antigen is nothing like it to semen and in this way, there is no cross-reactivity with other body fluids. 

Medico Lawful Significance of Detection of Sperm and Semen

Rape, sodomy (Anal intercourse), bestiality (Sexual relations by a human with lower animals like dogs, calves, sheep, and so on.) In case of false statements against a woman. (Sexual relation in blood relation) and sexual murders. 

Where to Look for Seminal Color-Damaged Spots 

Clothes: Bedsheet, cushion cover, underwear, drying cloth. 

Body: Thigh, vagina, perineum, public hair. 

Scene of Crime:  On the floor or grass and so on. 

Forensic detection of sperm assault evidence gives a detailed account of the kit as keeps after:

Sperm hy- liter is designed to make ready positive seeing whom a person is of sperm using a nothing like it monoclonal antibody that has been chemically ticketed with an Alexa 488 fluorescent dy 4-6-diamidino -2 phenylindloe DAPI that will stain all cell nuclei this is a fluorescent analog of the KPIC stain currently used in most DNA forensic laboratories. By combining both fluorescent spectra of Alexa 488 falls right for one’s need, comfort within the emission maximum for fluorescein all cell nuclei can be seen in the DAPI channel and using specialized dual filter 6 cubes, epithelial nuclei and sperm can be viewed in the mind at the same time. 

Although semen can easily be taken to be through testing of sperm may not always be possible. Forensic science. i.e. explains that semen in men who have had a vasectomy does not have within sperm. So, if like this further confirmatory test must be done. 

Labeling, Packaging, and Storage of Evidence

Evidence must be rightly labeled and packed in order to make certain that evidence is not lost, damaged or contaminated until putting one’s hands-on by the laboratory personnel and to give support to ( a statement) that good results and the chain of custody compliance to the evidence we have the right to use in a court of law. As an outcome of that all experts have taken part with the need to respect strict procedures that will be briefly discussed:

1. Each evidence must be dried before making it into a parcel. If a damp swab or other biological evidence is placed in a plastic or glass vessel, it will make come into existence a specially supported environment to the development of bacteria and possible evidence should be become ice (e.g. hygiene put soft material round or tampons with blood. 

2. Paper foldable self’s, packages are supported for biological evidence instead of plastic or glass vessels since paper let us still in the same way humidity to evaporate. Plastic or glass vessels could be used to process of Parceling physical evidence. 

3. For debris such as hairs, leaves, and threads a bindle can be used and then put into a paper process of Parceling (double packaged). 

4. All evidence should be one at a time sealed. 

5. Self- sealing covers for letters or right adhesive should be able with tap water or made wet very thin net-like material and not saliva to put a stop to the contamination of DNA. 

6. Evidence should be made ticket giving name with at least case one attacked persons one giving test names, group time-stamp and time, sample type, evidence number, and the placing from which the evidence was in order on the one attacked person’s body. Ideally, a barcode should be used. 

7. The request forms should be carefully made full. 

8. The one giving test should put the request form together with examples inside the separate kit before sealing it. 

9. Packages should not be joined with a bit of wire and must be signed across the seal to detect possible fraud. A biohazard name-giving ticket must be joined to the process of Parceling if needed. 

10. Each necessary thing should be kept in a right and safe place with adequate conditions of environmental conditions. (E.g. DNA examples are either stored in a refrigerator at 4° C or an Apparatus for keeping things cold at 20°c to reduce microorganism growth rate and to keep away from DNA degradation). 

11. The necessary things should be shipped to the laboratory as soon as possible. 

12. Regardless of the transport suggests it is important to make certain that samples are not exchanged switched from time of group to receipt in the laboratory. 

13. All individuals taking care of examples must sign the right chain of custody report. 


Due to its high intensity, the ability to be taken about forensic light source makes the discovery of biological color-damaged spots in darkness and daylight and can therefore not only be used in the laboratory but also at the crime place that is not able to be made dark picture is optimum when apparatus for making liquid clean are selected that solid masses the bright excitation and ambient light careful detection of Semen stains or under-clothes of group rape one attacked person on their grouping by simplest and most old ABO grouping careful way in addition to using DNA fingerprinting got to answer to the care. It proved that the accused person was taken part in the rape case. 


Question. 1. Why is DNA so Important, and What Does it Prove? 

Ans. Each person has their own special DNA, which is genetic code. After the crime testing building takes to be the same and gets at the details of a DNA profile from a person likely wrongdoing law enforcement can use this evidence to prove that a person likely of wrongdoing was at the place of the crime or had contact with the survivor. If there are no suspects in the case men of science at the crime testing building can look for the DNA profile in the CODIS database for a possible match to other crime place evidence it is important to note that not all rape necessary thing yield DNA evidence but the existence per being away of DNA does not one and only prove that a crime did or did not occur. 

Question. 2. Sexual Assault Case be Prosecuted if DNA Evidence is Not Found? 

Ans. While only the part of the country attorney’s office can for certain come to a decision about whether or not the offender will be put in motion once an assault is stated to the police DNA is just one part of the evidence in a larger investigation. When determining whether or not to put the PROSECUTE a case the part of the country attorney office will also take into account as the person still living account if the assault in company with any other evidence that may give support to this account (forex. , physical materials that link the 2 parties are a crime place, such as soft floor covering threads or grass color-damaged spots or a toxicology kit. If one was completed not all sexual assault evidence getting together necessary things yield DNA evidence and the being away of DNA does not mean that no crime occurred. 

Question. 3. If A Survivor After Having Sexual Assault Evidence Getting Together Kit Completed At A Hospital Would No Longer Like To Move Forward With The Case And There Are Support Witnesses, Can Law Enforcement Go Forward With Matching DNA Examples In The CODIS Database Coming Out From The Sexual Assault Evidence Getting Together Kit Then Discover A Person Likely Of Wrongdoing And Go Forward To Trail? 

Ans. If a survivor changes their mind about moving forward on a case after making a police written statement we would support them to make a connection with a local rape crisis center to help get through knowledge of their rights and to help advocate with police to request that the case not be made an observation of further. There are a variety of Case-specific points to be considered that might come up and so it is important to make a connection with someone to talk through this. 


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