RICHFIELD, Ohio - Gunshot residue tests, which are often performed at crime scenes to determine whether a person was involved in a shooting, do not confirm whether that individual fired a gun. Instead, the tests only verify whether someone was in the presence of gun fire.
"Someone could be near a gun when it's discharged but not be the shooter," said Jeff Lynn, lab quality assurance manager at the Bureau of Criminal Investigation and Identification in Richfield. "They could also have gunshot residue on another surface and come in contact with that surface and pick it up themselves."
Criminal investigators use an adhesive tape to dab an individual's hands for gunshot residue, usually within hours of an incident.
"We can also do [a gunshot residue test] on other objects, too, such as clothing and cars," said Lynn.
The tape is then sent to BCI, which performs nearly all gunshot residue tests for criminal cases in northeast Ohio, using a scanning electron microscope.
"[The test] can be helpful in a lot of cases where we have no idea what happened or who may have been involved," said Marty Lewis, a forensic scientist at BCI who's responsible for completing the tests.
In light of the Cleveland police high speed chase and shooting that left two people dead earlier this month, the gunshot residue test is a highly-anticipated part of the investigation that is led by BCI. Police fired 137 rounds at Timothy Russell and Malissa Williams. It's unclear whether they were armed, but no gun was found in their car after the shooting.
BCI would not comment on its investigation, but a spokeswoman said it would be several months before it releases its complete findings, which would include a gunshot residue test.
Three elements – lead, barium and antimony – must be present for the test to be positive.
"The test itself is somewhat simple," said Lewis who added the test could take hours or days depending on the sample.
"If there's only gunshot residue present or a lot of gunshot residue present, [the test] will go very quickly," said Lynn, who stressed that the test must be performed in conjunction with a forensic scientist who analyzes the results.
Unlike popular TV shows like "CSI" or "Law & Order," where crime scene are quickly assessed with definitive results, Lewis said reality is different.
"A lot of things here remain unsolved, even with all of the skills and equipment we have," said Lewis who added that crime scenes may lack enough evidence to convict a person.