The Tennessee Bureau of Investigation will have completed by the end of the week the ballistics and gun shot residue tests, which will go a long way in determining whether Sahel Kazemi committed suicide or was murdered.
Kazemi was found dead on Saturday afternoon along with former Tennessee Titans star Steve McNair. Metro Police have determined McNair’s death to be a homicide, but have not yet made a determination on the category of Kazemi’s death.
McNair was found with four bullet wounds — two to his head — while Kazemi suffered a single gunshot to her head.
Police spokesman Don Aaron said the ballistics and gunshot residue (GSR) tests being conducted by the TBI will be “important” in determining the cause of Kazemi’s death.
“Once we see the ballistics testing report, once we see the gunshot residue test report, we may be in a position to make some conclusions regarding the classification of Ms. Kazemi’s death,” Aaron said. “I’m saying we may be. These are not going to be tell-all.”
TBI spokeswoman Kristin Helm said those test results would be provided to Metro by the end of the week.
Ballistics tests match bullets to gun
The TBI ballistics test is used to determine whether bullets found at a particular crime scene match a specific weapon. The tests also provide other information, such as at what range a gun was fired.
Helm said TBI scientists would take a gun recovered at a crime scene and then attempt to match the type of ammunition used in a crime.
After acquiring the same kind of ammunition, laboratory workers would fire the actual gun used into a gigantic water tank. If the markings and striations from the newly fired bullets match bullets recovered at the crime scene, then the TBI can determine the shots came from a specific gun.
Metro Police found the gun believed to have been used to murder McNair under Kazemi’s body on Saturday. Police announced Monday that the gun was purchased by Kazemi on Thursday, just two days before the crime took place at McNair’s condominium on the corner of Second Avenue South and Lea Avenue.
Five shots were fired and all five struck either McNair or Kazemi, police said.
Aaron also said investigators did not believe the bodies of McNair and Kazemi were moved before detectives arrived.
GSR tests becoming more useful
In the case of McNair and Kazemi’s deaths, the GSR test appears to be of essential importance, because it may be used to determine who fired the gun.
Metro officers at the crime scene would take swabs from areas where the gun was fired, presumably including Kazemi’s body.
According to Helm, those swabs are run through a chemical test to search for three residue components, which come out of a gun cartridge when it is fired.
The GSR tests, which have become increasingly more accurate, could determine if Kazemi fired the semiautomatic handgun recovered at the scene.
GSR tests are not 100 percent accurate, Aaron admitted, but have become more useful of late. Helm said the test accuracy has improved, not because of better technology, but because crime scene investigators know how to properly preserve and collect evidence.
GSR tests can be manipulated if the residue comes into contact with other variables, such as water or blood.
“When you’re testing the GSR, the results are only going to be as good as the evidence collected,” Helm said, adding the tests could determine the range at which a gun was fired as well.
On Monday, Aaron said police had an idea of what took place inside the condo, but were waiting on more test results and information before disclosing their findings. As recently as Monday morning, detectives were at the crime scene continuing the investigation.
“We think we have an idea of how things went down in the condominium as far as the gunshots,” Aaron said. “I’m not at liberty at this point to discuss that with you. But we think that we’re beginning to put the pieces of the puzzle together as far as that particular aspect.”
McNair and Kazemi were engaged in a “dating relationship” which lasted several months according to Metro Police. Just two days prior to the shootings, Kazemi was pulled over for a traffic stop and eventually arrested for driving under the influence. McNair bailed her out of jail and, according to police, Kazemi purchased the handgun later that day from a private seller.
Aaron said he didn’t know whether the transaction between Kazemi and the private seller was a legal transaction.