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Forensic Evidence: Ballistics and Firearms
Transcript of Forensic Evidence: Ballistics and Firearms
What happens when they can't find the bullet?
When the bullets are missing, the impact they made can still lead investigators to find what kind of bullet the criminal used, and therefore the type of gun as well.
The impact a bullet made on a surface can indentify exactly which gun the criminal used. Every firearm produces a slightly different and unique pattern on the shell-casing it fires; the bullet will in turn leave a distinct pattern on anything it hits. Once scientists have identified these markings they can easily match them to the appropriate firearm.
Forensic ballistics can also be very useful in reconstructing a shooting that resulted in a gunshort injury, whether it is fatal or not.
Tissue on the human body can change the way a bullet travels; how fast, how far, and direction.
If a firearm is used to shoot a person, the wound would create backspatter of brain tissue, fat, muscle, bone fragments,
skin, hair, and even ocular tissue, this can be recovered from the gun and also the shooters hands.
Wound ballistics is particularly useful in suicide cases.
The power of ballstics
Did you know...?
After refferring to the Integrated Ballstics Information System, investigators noticed that the same weapon was used in a bank robbery only one year ago. A police officer was murdered but there wasn't sufficent evidence to convict anyone since the shooter had ran and no one could identify him.
The ballistics expert on this case was able to identify the weapon by analyzing the bullet itself, by reading the pathology report, and by recreating the scene.
Calvin Goddard 1920's
What is Forensic Ballistics
In forensic science, the study of ballistics is the study of motion, dynamics, angular movement, and effects of projectile units (bullets, missiles, and bombs). There are many applications of ballistics within a criminal investigation.
Ballistics Case; Fictional Example
On January 6th of 2013, a TD Bank located in Ajax was held up by a gun man who robbed them of $3460. The gun was fired 3 times but by the time the police had arrived, the shooter had taken off. Luckily, there was a young man who was able to provide enough information of shooter for the police to identify him as 32 year old Robert Banks.
The ballistics investigators also matched the bullet imprints from the wall to a Walther PPS Centrefire Handgun which was found in the glove compartment of Banks' vehicle.
Ballista is latin for a large military weapon or cross bow
- Philip Gravelle was the first to analyze bullets side by side when he created the first comparison microscope.
- Calvin Goddard used the comparison microscope in 1927 to analyze bullets in a
- Some of the greatest scientists and mathematicians in history that are associated with the development of ballistics on its own before the creation of firearms, include Leonardo da Vinci, Galileo, Isaac Newton, Francis Bacon, and Leonard Euler.
- Many rulers encouraged the development of ballistics in an effort to have better armies.
- The development of ballistics grew significantly at about the time that firearms were created and introduced into warfare near the beginning of the fifteenth century.
In 1537 an Italian scientist, Tartaglia wrote a book in which he said that the trajectory of a bullet was really a continuous curve. Tartaglia was a ballistics consultant to the Italian principality of Verona
He discovered that the elevation angle needed for a gun to acheive the maximum shot range was near 45 degrees. In this process he also noted that the shot trajectory was continuously curved.
The discovery and development of ballistics is long and involves the discovery of trajectory,velocity,and the ballistic pendulum
When bullets are fired, experts investigate the bullet in order to:
- Identify the type of gun used and if it was used in other crimes
- The amount of damage that was done to the bullet when it hit a hard surface (which can help determine where the shooter was standing, what angle the gun was fired from, and when it was fired
- Residue on the bullet can be studied and compared to residue on the hand of a suspect, the gun, or any object that was close by when the firearm was used.
This information helps experts to uncover the identity of the shooter.
After suicidal gunshots to the head, bloodspatter on the hands was
found with the naked eye at the time of autopsy in 14–35%
Investigators may also direct attention to the shoes and
pants of a suspect because these objects are likely to be in the downwards parabolic
flight path of the droplets
(similar to the parabolic pattern of a bullet
Nicola Sacco and Bartolommeo Vanzetti were arrested for the murder of security guard Alessandro Berardelli and the robbery of $15,766.51 in South Braintree, Massachusetts during the afternoon of April 15, 1920. They were sentenced to death in 1927. Many were outraged by this and Govenor Alvin T. Fuller postponed the executions .By the time the case was being reconsidered by the committee, they had made many imporvements in firearms examinations and they now knew that an automatic pistol could be traced if the bullet or casing was recovered. The committee appointed to review the case, used the services of Major Calvin Goddard in 1927. Major Goddard used Philip Gravelle's comparison microscope and helixometer, to make an examination of Sacco’s .32 Colt, the bullet that allegedly killed Berardelli, and the spent casings allegedly recovered from the scene of the crime.
The Defenders of Sacco and Vanzetti claimed that the bullet and cartridge case linked to Sacco's pistol were switched with genuine evidence by the Massachusetts police. Goddard fired several test bullets from Sacco's gun into a wad of cotton and prepared them for a comparative examination. He then put the ejected shell casings on the comparison microscope next to casings recovered at the South Braintree murder scene. Then he analyzed them carefully. The third bullet matched the rifling marks found on the barrel of Sacco's .32 Colt and the firing pin marks on a .32 spent casing recovered from the murder scene also matched a test shell casing fired from Sacco's Colt.Even the defense expert agreed that the two cartridges had been fired from the same gun. The second original defense expert also agreed. The committee upheld the convictions. Nicola Sacco and Bartolomeo Vanzetti were found guilty and executed via electrocution in Massachusetts on August 23, 1927.
One high-profile case the IBIS technology was used in was the investigation into the deadly shooting outside the Duke of York tavern in Toronto’s Leslieville neighbourhood.
Thirteen rounds were fired on the evening of Oct. 25, 2008, leaving a young woman dead and four other people injured.
Within three days of the shooting, police had issued a warrant and the un named suspect turned himself in.
But investigators were unfortunately unable to locate gun for weeks, until it turned up in an unrelated investigation.
"When the gun came in, it was recovered in a search warrant that was involved in a robbery," said Det. Mike Grierson, a guns and gangs investigator in Toronto.
When it was then analyzed using the IBIS technology, it became clear that the gun had been used in the Duke of York shooting, as well as a separate shooting in northwest Toronto.
it was said that this type of information that police never had access to in the past, which previously left investigators facing gaps that would otherwise be hard to fill.
At the trial, Kyle Weese, the man accused in the Duke of York shooting was convicted of the second-degree murder of Bailey Zaveda, as well as four counts of aggravated assault.
Robert Banks was charge with theft under $5000 and with First degree murder. Banks' was sentenced to life in prison with the possibility of parole in 25 years
The use of forensic ballistics and firearms has drastically improved over many years. Without this advance in forensics many cases may have remained unsolved. It is a fascinating combination of science and mathematics that has led to great discoveries over the years
http://www.hornady.com/ballistics-resource http://library.med.utah.edu/WebPath/TUTORIAL/GUNS/GUNBLST.html https://www.federalpremium.com/ballistics_calculator/