The three unsolved rapes in Annapolis, Baltimore and the Eastern Shore town of Denton appeared to be isolated attacks - until the DNA tests came back.
Now, investigators are seeking a serial rapist.
"Something puts him in wide-ranging locations," said David Cordle of the Anne Arundel County state's attorney's office, one of several agencies investigating the attacks, which took place from 2004 to 2007. "Is he a delivery person? Does he have a route? Does he have family there? Friends?"
Nearly a quarter of the state's 1,667 DNA matches have linked one unsolved case to another, with no name attached. While such "hits" do not deliver a suspect, they may enable new insights, in much the same way that ballistics tests can link a gun to multiple crimes.
"It brings together investigators," said Greg Shipley, Maryland State Police spokesman. "You are able to compile evidence that gives them a much more complete picture of the suspect."
In the unsolved rapes, investigators now are seeking the public's help in cold cases separated by three years and more than 70 miles.
In each of the attacks, a woman in her 40s was walking alone outside after dark when she was picked up by a man or two men in a vehicle, driven to a secluded spot and assaulted.
Investigators suspect that the same SUV was used in the Baltimore and Denton assaults, and believe the man whose DNA they have now matched was the driver, said Cordle, chief investigator of the Anne Arundel state's attorney's office. They think he was the passenger of the car described in the Annapolis attack.
The Annapolis assault, which occurred about 2 a.m. on Nov. 25, 2004, was first. A 41-year-old woman left a friend's home and was heading home on Forest Drive near Tyler Avenue. Two men in a small red car stopped and pulled her inside. The passenger assaulted her while the driver waited, said William Johns, a retired Annapolis detective working in the prosecutor's office.
The next assault, which occurred about 10 p.m. on Feb. 6, 2005, was in Baltimore. A 41-year-old woman left the Rockin Robin Cafe in Brooklyn and was walking along nearby Patapsco Avenue while hoping to find a cab. She was plucked off the street by two men in a large, dark SUV, Johns said. Both assaulted her, she told police.
Two years later, about 10 p.m. on April 9, 2007, a 44-year-old woman unable to reach her boyfriend to pick her up from a Royal Farms store on Market Street off Route 404 in Denton started walking home. She dropped a few items. A man in a large, dark SUV stopped, helped her, then gave her a ride. She was raped, Johns said.
Of the five rapes reported to Denton police in the past decade, only this one is unsolved, Deputy Police Chief George W. Bacorn Jr. said.
Johns said investigators don't know why there is a 26-month gap between the Baltimore and Denton assaults, or why the man has not been linked to another attack in nearly three years.
"That's what's interesting," Cordle said. "He just kind of dropped off. Maybe he stopped offending, is incarcerated, or he's dead. He might have moved. He might be incarcerated for an offense for which DNA was not taken."
Police do not know if he attacked other women who did not report it, Bacorn said.
Maryland began to require DNA samples from convicted sex offenders in 1994, according to Shipley. But the law has since expanded to include people charged with violent crimes and burglary. If the alleged rapist is charged with any of those, investigators will have a name to go with the genetic profile.
The Baltimore and Denton crimes were linked first, not long after the final assault. The Annapolis link, established about a year ago, was made possible by a federal $78,000 grant awarded in 2007 to the Anne Arundel County prosecutor's office to re-examine cold rape cases dating to 1980.
Anyone with information is asked to call Cordle and Johns at 410-222-1740; Baltimore police sex offense unit at 410-396-2076, or Denton police at 410-479-1414.