The only description a store clerk gives police of a robbery suspect is that he had a napkin wrapped around his hand that was holding the gun and he was smoking a cigarette.
Police find a bloody napkin in the store and a burning cigarette butt in the alley, where the suspect ran from the scene. DNA from the items match each other and are entered into the database which identified a man living in Illinois.
It sounds like an episode of “CSI: Miami” when fictitious Horatio Caine takes off his shades and says “Smoking proves hazardous to him,” but that describes a real case in Linn County.
Millions of people watch the popular TV crime scene investigation shows every week, forcing prosecutors and investigators to struggle with the “CSI factor” all the time. They say what the jurors expect based on the TV shows and what they can retrieve in reality are two different things.
“In the last 12 years or so, jurors have this expectation of physical or forensic evidence because of the CSI factor, as we call it,” Assistant Linn County Attorney Nick Maybanks said. “We always go over that during jury selection to lower their expectations. It’s not always possible to have physical evidence, and we try to tell them eyewitness testimony is just as valuable.”
Ron Johnson, Cedar Rapids crime scene investigator, said fingerprints can be found at a crime scene but many don’t have the ridge line details, which are the loop patterns in the skin that makes everyone’s prints unique, to make a match. Getting a good print also depends on the surface. It’s more likely to get a fingerprint or palm print off a non-porous surface like glass, plastic and steel. (Story continues below photo)
“Many times, the print might be smudged or it could be a partial and not everyone has perfect ridge detail,” Johnson said. “Some people’s prints are worn down, like brick layers or construction workers, and others just have fine ridges.”
Dennis Kern, criminalist with the Iowa Division of Criminal Investigation, said investigators in the TV crime programs can establish a time of death, find fingerprints on a weapon and match DNA from a hair to the defendant, which is usually pure fiction.
“Time of death is extremely difficult because it depends on temperature. Cooling slows it (decomposition) down, heat speeds it up and size of the person affects it,” said Kern, also a retired Davenport police lieutenant and latent print examiner. “The heat this summer was a factor. Part of a criminalist’s job is to explain why we don’t have it.”
However, Kern did find a print in a Marengo murder case in which there was little physical evidence and it may have influenced the jurors in their guilty verdict.
A print matching Jessica Dayton, convicted 2010 in the beating death of her former boss Curtis Bailey, was recovered using ultra-violet imaging on a box of plastic wrap. Testimony revealed she and two co-defendants initially tried to wrap Bailey’s body in plastic to contain the blood.
Maybanks said sometimes he’s surprised by the shows’ influence. There was a sex abuse case in which there was some discussion by jurors who thought police should have checked for fingerprints on the girl’s private parts.
“That’s not possible,” Maybanks said. “We always try to get the evidence if possible and we’ll even wait to charge someone until we get the results. It’s usually easier to get confessions if someone is confronted with physical evidence.”
Kern said every once in a while he gets unexpected evidence. A woman was stabbed to death in Bettendorf and a piece of skin from the suspect’s hand was found stuck on the body.
“Sometimes, when you’re looking for one thing, you find another,” Kern said. (story continues below photo)
Hamburger bun print
Johnson helped process the Cedar Rapids scene in which the infamous footprint on the hamburger bun led to the conviction of Carloss Robinson in 2000 for stabbing to death a young woman. Robinson had stepped on the bun while cleaning up.
Maybanks said he had a case in 2006 with more evidence than could be imagined. A man stabbed his girlfriend 52 times. He cut himself, leaving DNA, then he was captured on cameras at an ATM, a convenience store and at a hospital when he went to get medical treatment for his injury, which created a timeline.
There was also evidence from the victim because she and the man chatted on a computer and it showed how a heated argument, involving money, started, Maybanks said.
Johnson pointed out even if a print has enough characteristics to be viable and the suspect is unknown, then it could take time to match it because the suspect may not be in a state or national database if he/she hasn’t been arrested.“It’s not instant like they show on TV,” Johnson said. “They won’t always be in the system. I enter prints during down time if they haven’t been identified, hoping to get a hit. There was a robbery in 2008 and I re-entered it a year later and it identified a suspect.”