In the predawn darkness of Nov. 15, 1972, two Chester County police officers were fatally ambushed in their Kennett Square department parking lot by a member of a gang so notorious it was chronicled in a Hollywood movie.

Last week, a ceremony outside the historic courthouse in West Chester called attention to the searing memories created when Ancell E. Hamm, one of the earliest members of the Johnston brothers gang, gunned down Officers William W. Davis and Richard J. Posey.

Nearly 200 people gathered for the tribute, including the officers' relatives and a veritable who's who of law enforcement involved in ending the Johnstons' reign of terror. Brothers Bruce, Norman, and David ran a decadelong, multimillion-dollar theft ring in the 1970s that escalated into murder.

The memorial program, which marked the second phase of Chester's County's Hero Plaque program, was capped by the unveiling of two 18-by-15-inch bronze plaques with the officers' names and a notation that they were "killed in the line of duty protecting the citizens of Kennett Square."

In September, Douglas H. Pyle, a 20-year-old Parkesburg officer killed in the line of duty in 1988, was honored.

The tributes arose in large part through the passion of two men: Jimmy Binns, a Philadelphia lawyer; and Tredyffrin Township Police Sgt. John Bailey, a longtime detective.

During a recent interview, Binns, well-known as a boxing promoter who played himself in Rocky V, said he was drinking coffee with Philadelphia Police Sgt. Mike Walton in 2000 when Walton asked whether he knew that Philadelphia Officer Daniel Faulkner had been killed on Dec. 9, 1981, by Mumia Abu-Jamal right across the street from where they were.

"I couldn't believe there was nothing marking the site," said Binns, who immediately called the officer's widow, Maureen Faulkner, to see whether she would approve of a permanent memorial.

She did, initiating a program that has so far honored 158 police officers and firefighters in Philadelphia, Montgomery and Delaware Counties, and New Jersey, Binns said.

Police officers choose a unique profession, said Binns, a speaker at the Posey and Davis tribute.

"In an eight-hour shift, they can give a life, take a life, or save a life," he said, making them deserving of permanent recognition.

Bailey, whose grandfather was a police officer in Radnor Township, can remember wanting to pursue a career in law enforcement as a 17-year-old student at Conestoga High School. At 18, he said, he took a ride along with Tredyffrin Township police and never looked back.

More than three decades later, Bailey said Binns' dedication to publicizing the heroics of fallen officers attracted his attention. A former president of Chester County Fraternal Order of Police Lodge 11, Bailey said he contacted Binns in hopes of adopting the Philadelphia program in Chester County.

"He couldn't have been more gracious and helpful," Bailey said.

With input from Binns, Bailey began making plans for Lodge 11 to honor Chester County's nine fallen officers, a process that took a couple of years.

Bailey said that because some of the officers died in remote spots, he wanted a central place for the plaques with easy public access. He said he was thrilled when the county commissioners granted a request for a swath of land along Market Street outside the historic courthouse.

"It's never, ever too late to pay our respects," Bailey said, vowing to keep the memories alive and continue the process.

Addressing the audience last week, William H. Lamb, who was Chester County district attorney when the two officers were murdered, said he was not surprised that the killings made national headlines 37 years ago.

"If two police officers could be assassinated - and that's what they were . . . - in Kennett Square, in the little sleepy borough in Chester County, it could happen anywhere," he said.

The slayings of three junior gang members and one member's girlfriend fueled the 1986 movie At Close Range starring Christopher Walken and Sean Penn.

Joan A. Davis, the sister of Officer Davis, said that even though the pain of her loss never goes away, she found solace in the large crowd that gathered last week.

"It makes you feel really good after 37 years to know that other people haven't forgotten," she said.

Brian and Richard J. Posey Jr., the sons of Officer Posey, agreed.

"It means a lot to us," Brian Posey said. "Rich was 12 and I was 5 when our father was killed."

Richard Posey said he and his brother felt that the tribute honored them as a family.

"We're grateful for all the efforts that went into this," he said.

The plaques yet to be dedicated include those for three state troopers, an officer from East Pikeland and North Coventry Townships, and a sheriff who died in 1887, Bailey said. He said the next ceremony would be held in the spring.

Contact staff writer Kathleen Brady Shea at 610-696-3815 or kbrady@phillynews.com.