Five months since a woman reported being raped at gunpoint at a popular Montgomery County park, authorities have put a face to the man they say committed the violent daytime attack.

But what they released isn't a regular composite. Montgomery County District Attorney Kevin Steele described it as "old-fashioned police sketch meeting modern technology."

The illustration, revealed at a Tuesday afternoon news conference in Norristown, was created with the help of DNA the assailant left at the scene of the crime in Norristown Farm Park. It was assembled through a relatively new process called Snapshot DNA phenotyping, which uses the ancestry of a genetic sample to predict a person's physical appearance.

An illustration provided by the Montgomery County District Attorney’s Office.
An illustration provided by the Montgomery County District Attorney’s Office.

The technology — which cost the prosecutors' office between $3,000 and $4,000 — has been used in almost 150 cases nationwide over the last three years, said Dr. Ellen Greytak, of the Reston, Va.-based Parabon NanoLabs, which used phenotyping in this case.

Of the cases that have gone public with their use of phenotyping, 20 percent have been solved, Greytak said. That includes at least two closed rape cases. Greytak said Parabon had not been used in any other cases in the Philadelphia area.

The service has garnered its share of critics. Some scientists have doubted the accuracy of phenotyping, while others said it could contribute to racial profiling, according to a 2015 New York Times report. In 2016, the American Civil Liberties Union cautioned against the use of phenotyping, especially in cases involving a person of color.

But for Montgomery County authorities, Steele said, it was their best option. He said police officers had been working to solve the case for months — interviewing hundreds of people, searching for nearby surveillance cameras, using dogs to track a scent, all to no avail.

"This is an approximation.  This is an effort we are making to try and get a lead," Steele said. "This won't end the investigation."

The DNA left behind showed the suspect was of "African admixed" ancestry — with 52 percent European and 45 percent African descent, Steele said. This is rare, he added, and could indicate the attacker had a recent European ancestor.

The assault occurred between 10:30 and 10:50 a.m. on Aug. 1 at the scenic park in Montgomery County, Steele said. While walking along Stony Creek Road, between Upper Farm Road and Lower Farm Road, the 19-year-old woman was grabbed from behind by a man wearing a black hooded sweatshirt, Steele said. He raped her at gunpoint, holding a black, semiautomatic weapon to her head with his right hand, Steele said.

"Random stranger attack involving a weapon, that's not the norm," said Kristen Houser, a spokeswoman for the Pennsylvania Coalition Against Rape.

Generally, about 60 percent to 80 percent of adult sexual assaults are perpetrated by someone known to the victim, Houser said.

The Aug. 1 assault was the first reported gunpoint sexual assault in Montgomery County in perhaps a decade, authorities said.

In the days afterward, the report put park regulars on high alert. Many flock to the picturesque trails there in warmer months to walk, jog, and bike. Meanwhile, investigators got to work, offering a $10,000 reward in hopes that a tip would help close the case.

Nothing substantive ever came. The reward is still out there, Steele said.

"This is a case that keeps us up at night," Steele said. "We need help."

"All rape is scary. I think this sort of sexual assault is not only terrifying for the victim, it is also disruptive to the entire community," Houser said. "It really shakes the sense of community safety to its core."

Steele asked anyone with information about this case to call Montgomery County Detectives at 610-278-3368 or West Norriton Police at 610-630-1701.

Cornfields and trails in Norristown Farm Park on Aug. 2, 2017, a day after a woman said she was raped in the park.
CLEM MURRAY/Staff Photographer
Cornfields and trails in Norristown Farm Park on Aug. 2, 2017, a day after a woman said she was raped in the park.