From 2006 to 2010, violent crime - murder, rape, aggravated assault - dropped 25 percent in Philadelphia, according to FBI Uniform Crime Reports.
In 16 surrounding towns, the drop-off was a mere 3 percent, and in Upper Darby, it jumped close to 30 percent higher.
Michael Chitwood, Upper Darby's outspoken police superintendent, suggests a possible irony. He said a major source of the township's crime was Philadelphia.
Chitwood was a rookie Philly police officer in 1964, and he said that today, he is still chasing Philadelphia criminals. He estimates 60 percent of the crime in Upper Darby is committed by Philadelphians.
The towns bordering the city are no monolith - urbanized Upper Darby hardly resembles classically suburbanized Abington.
What they do share is an alluring asset - proximity to the city, which police contend is a source of their headaches.
"That problem's the same with all the first-ring communities," said John Livingood, deputy chief in Abington Township. "We're not different from our neighbors."
Statistical evidence is wanting because the FBI data report numbers of crimes but not the hometowns of criminals.
"I think it's always easy for people to blame Philadelphia," said Jerry Ratcliffe, chairman of Temple University's criminal justice department. "Any police department thinks it is a net importer of criminals."
But officials in the border towns say their arrest records support their observations.
"Philadelphia is a great neighbor and a great police department," said Frederick Harran, Bensalem Township's public safety director. "We work extremely well together." And, evidently, often.
Last year, of the 2,949 arrests in Bensalem, 1,523 involved Philadelphians - an 11 percent increase over 2010. "Those numbers are unbelievable," he said.
In Cheltenham Township, about 50 percent of the adults arrested in 2011 were Philadelphians, Police Chief John Norris said.
Cheltenham has two shopping malls on the edge of the city, and shoplifting is one reason its crime numbers are up.
Law enforcement officials and criminologists caution that the FBI data must be viewed skeptically. For one thing, police departments report the numbers on an honor system.
"It's an imperfect system run by the feds, who don't know about crime," Norris said.
Chitwood said he did not need statistics to tell him about crime problems, and Upper Darby and other border towns are taking some untraditional steps to combat it.
Livingood said that his department had officers stationed in all the schools and that the township had established a Citizens Victims Unit. Any victim of crime, be it a break-in or identity theft, will get a call from someone in the unit, said Jan Harris, 52, a township resident who once was a break-in victim.
"We're trying to help them not to be revictimized," she said.
In Upper Darby, Chitwood persuaded Mayor Tom Micozzie to convert an empty building in one of the township's roughest neighborhoods into a community police station.
"At first, they thought I was a cop," said Nashid Furaha-Ali, the civilian who is the township's police liaison officer and who staffs the building 40 hours a week. He said it had taken time, but that in the six months he's been there, the locals had come to trust him.
Chitwood said that in his time, crime hasn't changed all that much; it's just gone through various cycles. These days, it's bumped up by increased heroin use and an epidemic of break-ins in the pursuit of jewelry and copper pipes.
Not that a 48-year veteran can't be surprised once in a while.
Recently, a woman and her three children showed up at Upper Darby High School and gave some students an impromptu anatomy lesson by stripping nude and chanting religious phrases in the parking lot. Police were called.
The family, it turned out, was from Philadelphia.
Said Chitwood, "I guess that's under the theory that all roads lead to Upper Darby."
Contact Anthony R. Wood
at 610-761-8423 or firstname.lastname@example.org.