DNA crime fighting gets faster and easier

NEW ORLEANS - DNA evidence used to be used for just high-profile crimes, but just last month, St. Bernard Parish used DNA evidence to arrest a man for multiple burglaries.

The science behind DNA crime fighting is getting easier and more accessible. TV dramas like "Bones" and "Almost Human" talk a lot about DNA, and LSU Health and Science Center genetics professor Paula Gregory said there is a lot of reality there.

"It has done so much to explain genetics to people," she said.

The science makes finding criminals easier.

"Criminals are usually pretty smart, and they try to cover up there fingerprints," Gregory said.

With DNA samples, any sort of biological material - from blood to hair, or even a broken fingernail - can contain the genetic material that places a person at the scene of a crime. Forensic scientists compare 13 parts of the human genome to make a DNA match.

"It's almost a slam dunk if you have this person's DNA directly at the scene of that crime and he had no other business being there," said St. Bernard Parish Sheriff's Office Chief of Operations John Doran.

The St. Bernard Parish Sheriff's office is excited that the Louisiana State Crime lab can now get to even the most common cases quickly.

"It used to be it took months and months and months, and you almost had to have a suspect identified," Doran said.

The department arrested Richard Williams using blood left at one burglary and then connected him to another burglary with other DNA evidence. His DNA was already in a database of all convicted felons and others arrested on certain felony charges.

"In the past, obviously things were prioritized in a way of the more serious crimes, but more recently even residence burglary cases that might have DNA evidence are coming back in a relatively short period of time, which is a great asset for us," Doran said.

"Louisiana's DNA crime lab is like a two-week turnaround, which is amazing. Quick, quick, quick to get results which is what you want."

Gregory said the process is becoming much easier.

"This is called polymerase chain reaction, which is just using the inside and using heat to break the two pieces of DNA apart, and they act as the template for the next copy, and then you can break those apart so it's an exponential copy and that's exactly how the cell does it," she said.

Those copies can be used to compare against a known suspect and/or the Combined DNA Index System, or CODIS. When scientists find a match, they say it's a one in five billion chance that they have the right person.

"It's one in the whole world other than identical twins," Gregory said - a statistic that's hard to ignore.

Of the DNA collected so far this year, State Police said 150 samples match up to people already listed in the National DNA Database.