Cops say DNA 'remarkable' in solving '98 rape

The DNA of Calvin Gadson finally caught up with him in the rape of a 15-year-old school girl, in a cold case unsolved for a dozen years.

Calling the find "remarkable," Capt. John Darby, of the Special Victims Unit, said yesterday that modern DNA analysis matched Gadson, 33, of 43rd Street near Brown, in West Philadelphia, with the DNA taken from the victim at Episcopal Hospital in 1998.

The victim's reaction?

"Surprise!" said Darby. "The victim was elated she was not forgotten."

The case demonstrates how convicts who think that they got away with crimes can still get caught, as DNA analysis - and police procedures - have become more sophisticated in the past 12 years.

Darby credited police teamwork with Gadson's Jan. 4 arrest.

It was about midnight on Feb. 1, 1998, when the 15-year-old girl and her boyfriend were walking near Reyburn Park in an area bordered by Sedgley Avenue and 20th Street, in North Philadelphia, Darby said.

Two assailants attacked the couple. The men took turns holding the boyfriend on the ground at gunpoint, and raping the girl, he added.

The rape victim was treated at Episcopal Hospital and forensic DNA evidence was obtained. At the time, neither victim could identify the attackers.

Thus began the long road to Gadson's arrest.

In 1998, a different technology was used to analyze DNA, and entered into a state police database, said Lt. Thomas McDevitt, of SVU.

Later, DNA was required from all convicted felons, either entering prison or those on probation or parole. As more DNA was collected, the labs - both government and private - developed a serious backlog.

Not until 2003 was a genetic profile developed for the 1998 rapist, "John Doe," said Darby. Using the profile, SVU investigators obtained an arrest warrant.

The next year, the FBI created a national DNA database, and required more genetic markers analyzed by labs.

Last June, state police lab technicians for the first time matched the DNA taken from the 1998 victim to Gadson, based on a new DNA sample from a prior conviction.

But, with national procedures in place, city police were required to confirm the initial DNA test. Armed with a search warrant last October, SVU officers had to track down Gadson and take a swab of his mouth.

In mid-December, the Philadelphia Police crime lab, which now conducts sophisticated analysis of its own DNA samples, confirmed that Gadson's genetic profile matched the rapist's 1998 profile.

SVU officers still had to show the victim a photo array and ask if she had consensual sex with any of them. She said no.

On Jan. 4, Gadson was arrested at home by officers with SVU and the 16th District. He was charged with rape, conspiracy, sexual assault, indecent assault and seven other counts, including firearms violations.

He is being held in Curran-Fromhold Correctional Facility on $150,000 bail.

"We're going back to a number of older cases that we have DNA for and retesting them with newer technology," said crime lab scientist Brian Pfleegor, who handles the DNA profiles. "It's an ongoing thing with us."

Police are continuing to search for the other assailant.