Most people assume they were born this way, with the instinct to kill; but that's not true, genetics, environment and trauma can all be factors in making a murderer. For example, most serial killers experience some sort of trauma as a child which can cause a huge impact in their adulthood. Different types of trauma can be linked to the 4 types of serial killers visionary, mission-oriented, hedonistic and power. Researcher Abbie Maroon worked with ex-FBI profiler Joe Navarro to study and find out how different types of childhood abuse can cause the different types of killers. Their results suggested that sexual abuse could be linked to killers who chose to sexually assault and rape their victims before and after death as well as anger killings which would have been performed in a rage, psychological abuse could also be linked to killers who were sexual towards their victims but can also be associated with financial gain killings. Physical abuse was also linked towards rape and lust killings, but with behaviours such as leaving the body at the scene and carrying out the act quickly.
However, genetics can influence a person's ability to become a killer. The gene Monoamine oxidase A (MAO-A) has been associated with a variety of psychiatric disorders which can be linked to killing. People with elevated MAO-A levels in the brain are more likely to become depressed, the same gene can also cause antisocial personality disorder. If you combine the effects of this gene with the environment a person grew up in and any traumaabuse experienced there is a high chance they will become a serial killer or murderer. An example of this would be Bradley Waldrum, who shot and killed his wife's friend and then attacked his wife with a machete. He admitted to the crimes and was charged with murder and attempted first-degree murder and was likely to get the death penalty, but his defence team asked for a scientific assessment, and it was found that he had a variant of the MAO-A gene which a forensic scientist then testified for that his combination of genes and trauma he had experienced as a child left him at higher aggression risk. This caused him to get a lesser sentence, meaning it played a significant part in a trial.
An example of a notorious serial killer from the 19th century is Jack the Ripper. Jack was situated in London during 1888 and murdered then mutilated a minimum of 5 women; the way the bodies were mutated suggested that whoever had committed the murders had a good amount of knowledge about the human body. He was an active murderer between August 7th and September 10th in and around Whitechapel district in East London, during this time several other murders took place which were believed to also be him but investigated under the nickname leather apron.
Jack the Ripper focused and murdered women of the night prostitutes which wasn't uncommon and usually went unnoticed due to them usually being alone with no families or homes but due to the brutality of these murders an investigation formed. Jack didn't just rape and murder these women, he mutilated them to a point where it was sadistic, and left the feeling that he had a hatred for women. The murderer, offering to pay for sex, would lure his victims onto a secluded street or square and then slice their throats. As a trophy, Jack often took the organs of the women, which adds to the theory that he knew the human anatomy as he was able to locate organs like the uterus and the kidney.
To add to the mystery, several letters turned up at the London Metropolitan Police Station (the Scotland Yard) describing pervious murders that had occurred and speculations about murders to come, taunting police officers and detectives who were on the case. Even after countless investigations into the murders his identity was never found, along with his motives. This happened in a time before forensic technology had been developed and advanced; meaning there was little way for evidence to be tested. There was no fingerprint scanning to see if it matched and left on the victim or their clothes, they were unable to test the blood to see if it was just the victims but also blood of other people. This mint the only plausible way of catching a killer was a confession ort catching them in the act. There have been several theories speculating the true identity of the killers including the Grandson of Queen Victoria, a Polish migrant and Victorian painter Walter Sickert; over 100 suspects have been named and tried but none guilty of the crime.
Jeffrey Dahmer was an American serial killer who was active between 1978 and 1991 and murdered around 17 males he predominately went for gay African American males at gay bars, shopping centres and lured them to his home with the promise of money and sex. He then gave them alcohol laced with drugs to sedate them and then he strangled then to death. He would engage in necrophilia wi6th the dead corpses before dismembering and disposing of them whilst keeping skulls or genitals as a trophy. He was also known for taking photos during all of his killing and aftercataract so he could relieve the experience. After his capture in 1991 he was sentenced to 16 life sentences before being murdered by inmate Christopher Scarver in 1994.
Dahmer claims that his compulsions towards this behaviour began when he was 14 but his parents s marriage caused it to go over the edge. However when Dahmer was in the womb his mother was suffering from mental illness and took 27 pills a day which may have led to these thoughts; due to her mental illness after birth Dahmer began getting neglected as his mother never wanted anyone besides her to touch him because of germs, this neglection at such a young age was potentially one of the most leading factors for him to act this was as it impacted the way he felt, thought and made all future relationships. By the age of 8, he had his first mental illness which just got worse overtime, so bad that he turned to drinking, however this caused his thoughts to turn into obsessions also leading him to his killings. In December 1978 Dahmer has joined the army and was deployed to Germany but he had become an alcoholic over past years which ultimately resulted in him being discharged in august 1981. His first murder occurred when he was 18 in June 1978; when he picked up a hitch hiker, took him to his parents house, got him drunk and when hicks tried to leave Dahmer hit his with a bat and then strangled him. He then proceeded to kill and dispose of two more people and it wasn't until September 1989 that he realised the error of his killings. This happened due to the fact he got put on trial for child molestation after a run in with a 13-year-old eventually leaving him on the sex offenders register. While waiting for the sentence from the molestation case he lured Anthony Sears to his grandmother's basement where he murdered and then sexually assaulted Anthony's body. Over the next two years his body count jumped from 4 to 17, in which he developed tactics of killing his victims and often ate the flesh of his victims. He liked to experiment with his victims while they were alive doing things such as lobotomies Abd injecting them with unknown substances. In May 1991, police were called to Dahmer's current resident as a naked Asian boy had been seen running from his house, the boy who Dahmer claimed to be 19 was actually the brother of the 13-year-old he had previously molested. The police however believed Dahmer and took a quick look around the property not wanting to get involved with homosexual acts. If only the police took a proper look they would have found the body of Dahmer's 12th victim, [putting an end to his killings, but they didn't and he got away with 5 more murders.
His spree was put to an end in 1991 when two polices officers spotted an African American man with handcuffs on wrists and followed up on his claims about Dahmer. Upon arriving at his place, he offered to get the keys for the handcuffs and the police entered his apartment where they saw multiple photos of dismembered bodies and other sexual acts occurring.
He was sentenced to 16 life sentences and only served 3 years as he was murdered by fellow inmate Christopher Scarver.
In the case of Jeffery Dahmer, the police got lucky by finding a victim of Dahmer as there was little evidence for the police to believe he was a suspect in the case and they didn't have the advanced technology we have today, however they had the ability to do a background check when they decided not to get involved with homosexual acts and with doing the background check they could of seen his sex offender status which may of helped his killings be put to an end quicker. This therefore means that is the police had better training and were not so reluctant to investigate a potentially homosexual man; they could have saved the lives of 5 more women. It makes you wonder if it was a fault in the police that Dahmer got away with what he did for so long or whether it was the lack of forensic evidence which could have stopped him and tell the police who the serial killer was. Or was it the fact his parents didn't care for him or the fact he had an untreated mental illness? All factors which can lead to a psychotic break and cause him to kill, sexually assault and do scientific experiments on his poor victims.
Over the years policing and criminal investigation became more and more advanced as new forensic technologies and tactics were bought in to play. They brought in rapid DNA testing. Developed in 2010, this meant instead of having to wait 8 months whilst paying a lot of money for a DNA test which may not even be helpful, they receive the results within 75-95 minutes which is particularly helpful. DNA profiling is one of the most used and heavily relied on sources to find a criminal, when DNA is found at a crime scene it is matched against previously convicted criminals and against the DNA of the new suspects for the case
One of the main techniques when finding a serial killer is to start off with criminal profiling, this allows the police officers on the case to tell if all the crimes are connected and that they need to be looking for one person or if they are looking for more than one person. It is most likely to be used when the criminal's identity is still unknown and can be connected to serious crimes. There are five main aspects into criminal profiling which help build up a criminal profile. It works like a machine with the different inputs causing different responses, which can lead to a suspect being found; to start off they need to gather all information linked to the crime such as where, why and how, they should also be collecting information on the background of the victim as it could lead to a potential suspect when matched with the rest of the profile. The second step in creating a profile is decision processing this is where the would replicate the crime scene layout including all items that were at the scene of the crime, things they may have looked suspicious or out of place and evidence (such as blood stains) which relate to the victim of the crime, why the criminal chose this method why they chose the victim, how the crime was committed and any links between other crimes that have happened in similar ways with similar traits meaning they may be connected. After decision processing they would use crime assessment in which they replicate and act out the crime. They then offender profile, this involves deliberating about the offender, they create a profile that describes them, including intelligence, age, geographical location, certain characteristics and gender. They then put it to use during the investigation which can help the investigators narrow down who they are looking for and where to look.
The police now also have access to automated fingerprint and facial recognition which allows fingerprint and face analysis to become more reliable than human analyzation. It is especially helpful as the fingerprint is stored on a system so if the criminal gets caught doing something in another country they could still identify them without knowing them. They also use fingerprint analysis when out in the field looking at a crime scene, using special techniques they collect fingerprints off objects that have been linked or were at the crime scene which get sent to a forensics lab so they can do the analysis. The use of CCTV allows potential suspects to be linked through facial recognition, as if the potential suspect has been caught on CCTV the police can use images from that and analyse it against other criminals they already have on record so they can determine if it is a new criminal or someone they have caughtinterviewed before. The police can also use these CCTV images to broadcast to the public who they should be aware of and what they can do if spotted.
When evidence at crime scenes has been collected, forensic analysis can be completed. Any hair or clothes fibres left behind can indicate general features of the individualsuspect who was at the scene. If they fibres or hair have any blood stains on it can then be used in a DNA analysis to determine whether or not they are related to the victim or if it is from the suspect. Analysis of the clothing can also help with the detection of if a knife or other sharp object was involved. The way the clothing fibres are damaged torn, ripped, cut can show the investigators that a sharp weapon was involved in the attack, it can also show the force used on the victim, if the clothes have been cut jaggedly it was rushed or if it's a clean slice it could have been quick and fast ect. Blood stain analysis can also determine these things. Many investigators are now trained in blood stain analysis; meaning that they are able to tell whether the victim was still, walking or running at time of death, which can help indicate if they actually died in relation to blood or if it could have been something else i.e. strangulationsuffocation, they can also use bloodstain analysis to determine how much force was used to cause the victim to bleed. Certain blood patterns mean it is detectable to find a potential weapon that may have caused death for example, impact patterns suggest that the victim was struck by an object on a blood source. The different types of blood stains all suggest a different thing so when a specialist arrives at the scene it is best to allow them to work as pictures and videos aren't as effective or easy to get the blood stain analysis from.
The study and improvement of Serology allows CSI's to determine the particular group the suspect may be in because of the Rh blood group system, it also allows them to find out if the victims have been sexually assaulted or raped as they can detect other bodily fluids e.g. sperm.