WATERVILLE — When an attorney for Ayla Reynolds’ paternal family announced Friday that DNA found in the toddler’s home might not be blood, it led many to ponder two questions:
• If it isn’t blood, then what is it?
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• If investigators found Ayla’s DNA, couldn’t they determine the type of substance it came from?
According to an expert forensic investigator, the list of possible substances is short and, if investigators were dealing with microscopic amounts, they could only confirm the type of substance if it was blood.
The questions were raised last week when Steve Bourget — an Augusta lawyer who represents the missing toddler’s grandmother and aunt — said police told his clients that DNA evidence found in the toddler’s basement belongs to Ayla, but it isn’t “necessarily blood,” he said.
Police haven’t commented on Bourget’s claim about the DNA evidence, but Department of Public Safety spokesman Steve McCausland said Wednesday that “there has been no change in any of our previous statements.”
In January, McCausland said investigators found blood belonging to the 20-month-old girl in the basement of 29 Violette Ave. — the home where the toddler reportedly was seen last. McCausland wouldn’t disclose how much blood investigators found, but said they used the chemical luminol to find it.
Melisa Staples, assistant director of the New Hampshire State Police Crime Laboratory in Concord, N.H., said DNA can be found in blood, saliva, semen, bone, hair roots and skin cells, but not much else.
DNA is also present in urine and feces, but it’s difficult for investigators to obtain evidence from those materials, Staples said. Urine contains a small amount of DNA and is difficult to find unless investigators have a large sample. Fecal matter is even less useful for investigators because its bacteria quickly destroys any DNA within the sample. Complicating matters further, urine or feces would be virtually undetectable if a crime scene was cleaned up before investigators arrived.
Blood and saliva, on the other hand, might withstand a cleanup, and the DNA within is “very stable over time, particularly in a climate that’s dry and not hot,” Staples said. “It can be stable for years and years.”
Dried saliva, however, would be difficult for investigators to find, because there aren’t chemical agents to detect its presence, she said. Investigators would almost have to find saliva by accident, she said.
Blood is much easier to find, she said. If investigators suspect the presence of blood, they can use chemical agents — such as luminol and phenolphthalein — to confirm their suspicions.
Luminol stimulates electrons within hemoglobin — a component of blood — and causes the mixture to glow. Luminol also reacts with bleach, copper, horseradish and more, so investigators at the scene often perform additional tests to confirm the presence of blood, Staples said.
One such test uses phenolphthalein — a chemical that turns color when it is mixed with other substances. Investigators will typically swab an area that is suspected to be blood, then apply phenolphthalein to the swab. If the swab turns purple, it’s most likely blood, Staples said.
Once the presence of blood is confirmed, investigators would swab a few more samples, then develop a DNA profile at the laboratory, she said.
In other words, if Ayla’s DNA sample came from blood, investigators would know it was blood, Staples said. If the DNA came from something else, such as saliva or skin cells, investigators might never know its source.
Bourget said Tuesday he didn’t know whether investigators told his clients what the substance might be, adding that he did not attend the meeting.
Ayla was reported missing on Dec. 17, 2011, by her father, Justin DiPietro. No one has been named as a suspect or a person of interest. DiPietro contends that Ayla was abducted.
Police say a kidnapping did not happen and they believe the three adults who saw her last — her father, aunt Elisha DiPietro and Courtney Roberts — are withholding information in the case.
Investigators also believe Ayla is dead. State police are asking that anyone with information call them at 624-7076.
Ben McCanna — 861-9239
bmccanna@centralmaine.com
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