Newspaper article Pittsburgh Post-Gazette (Pittsburgh, PA)

Technological Advances Speed the Processing of DNA Evidence Robot Aids Analysts in Allegheny County Forensic Laboratory

Newspaper article Pittsburgh Post-Gazette (Pittsburgh, PA)

Technological Advances Speed the Processing of DNA Evidence Robot Aids Analysts in Allegheny County Forensic Laboratory

Article excerpt

Over the course of two days, two women in Ross and another in Hopewell reported that a man they had never seen before had broken into their homes, held them at gunpoint and raped them.

The victims offered only rough physical descriptions of the assailant, and there were few witnesses. Ross police developed a suspect, whose car matched one seen leaving the scene of one attack, but their scant evidence linking him to the crime was not enough to charge him.

"There was no smoking gun," said Detective Brian Kohlhepp of the Ross Township Police Department.

But nine days later, police got just that: A link made through DNA found on the two victims in Ross matched the profile of 38-year- old Arthur Henderson, who had submitted a DNA sample after police obtained a warrant. He was in police custody within 12 hours.

In spite of improvements in technology, DNA investigation remains a time-consuming and tedious process fraught with difficulties. The average turnaround at the Allegheny County Medical Examiner's Office lab for a crime scene sample was 313 days in December.

In this rape investigation, the seriousness of the case sped up the process, but the lab is beginning to work through a backlog and improve efficiency with new technology -- including a robot that can extract DNA many times faster than humans working manually.

Knowing they had "an active serial rapist on our hands," analysts prioritized the case, said Karl Williams, who heads the Allegheny County Medical Examiner's Office. Two analysts worked through the weekend processing samples to complete the analysis.

"It was crucial to the case," Detective Kohlhepp said. "Without the DNA evidence, we would have continued to investigate [but] we would not have had enough to charge him."

Their swift work may have prevented future attacks. A man matching his description was reported "acting suspiciously" in nearby communities, according to Detective Kohlhepp.

Mr. Henderson's family said he is innocent, said his attorney, Blaine Jones, who indicates he plans to have his own analysts examine the DNA evidence.

New equipment purchased with a series of grants will help the Allegheny County forensics analysts speed up work on many other cases, including more routine burglaries and years-old cold cases, laboratory manager Janine M. Yelenovsky said.

Key in the effort is the Biomek 3000, a robot that can extract DNA from as many as 60 samples in about two hours. The same work, done manually, would take weeks, Ms. Yelenovsky said.

Extracting the DNA is a bit like cooking -- you add ingredients, let them sit, shake them and let them sit some more.

Analysts use chemicals and other processes to strip away all other cellular material from a sample so all that remains is DNA. The process, done manually, takes up to 20.5 hours. The robot can extract DNA from a sample in about 2 1/2 hours and performs much of the labor, such as adding chemicals to the samples.

The robot was not used to process the DNA samples from the assaults in Ross, in part because each sample would have had to be segregated into its own tray. With a small number of samples, it's faster to process them manually. …

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