AFTER ONE OF his officers was arrested on abduction and sex charges in 2006, Prince William County Police Chief Charlie T. Deane went to the county jail to personally fire him. And instead of shying away from the incident — as would be the wont of some chiefs — Mr. Deane thought it important that the public hear from him. “By law, I cannot comment on the individual’s personnel situation . . . ,” he said, “However, I will say that it is my personal and professional opinion that anyone who engages in this type of abuse of authority should not be a law enforcement officer.”

That straightforward candor, the unblinking belief that police must maintain the trust of the community they serve, has been the hallmark of Mr. Deane’s remarkable tenure. After 42 years with the Prince William department, 24 as its head, Mr. Deane, the longest-serving chief in the Washington region, is retiring on Sept. 1.

Mr. Deane, as The Post’s Josh White chronicled in disclosing the news of Mr. Deane’s retirement, ran the department during a period of enormous change, in which both policing and Prince William were transformed. The son of a sheriff who knew early on that he wanted to follow in his father’s footsteps, Mr. Deane started his career as a state trooper in 1966, switching to the county police four years later; his background as a criminal investigator grounded his approach to his job but never limited him. He had the ability, in the words of Philadelphia Police Chief, and former D.C. police chief, Charles H. Ramsey, to “adjust, adapt and grow.”

Nowhere was Mr. Deane’s leadership more apparent — or more critical — than during the horrible weeks of 2002 when two snipers preyed on the Washington region. Mr. Deane was a stabilizing figure during that period, and it’s a testament to the professionalism of his department that the first prosecution was for a Prince William killing.

“The sad thing is, the biggest lesson from this is that two fools with a rifle can put an entire region of the country in a state of absolute fear,” he told The Post after sniper John Allen Muhammad was executed.

There were other high-profile moments that showed Mr. Deane’s unflinching honesty and integrity. Instead of being defensive about his department’s fumbling of a case that contributed to the death of a 13-year-old girl, Mr. Deane admitted the mistakes and put in place reforms to ensure they would not be repeated. When county officials wanted police to check the immigration status of residents and arrest those who were in the country illegally, he wasn’t afraid to push back at a policy he saw as bigoted and sure to cause problems for law enforcement.

“I think I know right from wrong. You have to treat people fairly,” he said. Amen and thank you, Chief Deane.