Recently, a New Mexico newspaper and the Associated Press covered what sounded like a light-hearted story. Apparently, someone attempted an armed robbery a Pizza Hut store in Las Cruces.
The police reviewed surveillance tapes but were apparently unable to identify the suspect. Then, they noticed that the suspect “face-planted” into a locked exit door before pivoting and using another door.
The officers swabbed the locked exit door for DNA evidence. The state forensic laboratory found human DNA on the swab. They then entered the sample into CODIS — the Combined DNA Index System, a nationwide database of known DNA samples. They got a match.
A 19-year-old man from Las Cruces was arrested by Albuquerque police last week. He is being held at a county detention center without bond.
The police also suspect the young man in another robbery that happened earlier the same day at a local gas station.
The young man has been charged with one count of attempted armed robbery, a third-degree felony, and one count of aggravated assault with a deadly weapon, a fourth-degree felony.
Would a face-plant into a door leave DNA evidence behind?
It might. It’s possible that skin cells and oil, left behind on the door, could yield enough for a DNA profile. However, it isn’t very likely. A bump into a door would probably leave no more DNA behind than is contained in fingerprints, and police rarely use the cells and oil from fingerprints for DNA profiling.
Even if the “face-plant” did leave behind some skin cells and oil, it probably wouldn’t be enough to develop a full DNA profile. That could mean that the suspect only partially matches the sample.
Assuming the DNA match between the door and the 19-year-old suspect is definitive — and we can’t necessarily assume that — it’s also possible that the young man left his DNA on the Pizza Hut door in some other fashion at some other time.
Hundreds of people a week leave their DNA or fingerprints behind on the doors of retail establishments. Depending on how often those doors are thoroughly cleaned, those samples could be there for an extended period of time.
It simply isn’t suspicious to have your DNA on the door of a Pizza Hut. Finding DNA on a Pizza Hut door isn’t remarkable. It isn’t surprising that any DNA found there would be tied to someone local.
If you thought this story seemed like a slam-dunk case, think again. There could be nothing here beyond the purely circumstantial.
Unfortunately, juries tend to trust virtually any species of DNA evidence presented to them. Without a defense attorney experienced in the strengths and weaknesses of DNA evidence, this young man could be in over his head.