Four senior police commanders with more than 100 years of combined experience have retired in the past month, creating vacancies at the top of the department that Chief Charles H. Ramsey has scrambled to fill through transfers and promotions.

The changes come at a critical time as Ramsey has credited his policing strategies and partnerships with city agencies with helping reduce District homicides and other crime. The city is on pace this year to have fewer than 200 homicides for the first time since 1986.

Ramsey said he was "sorry to lose" the commanders but felt confident about those he promoted to fill their slots.

"It was time to let some young and more energetic people to step into leadership positions to help move this department forward," the chief said.

Ramsey lost two top-ranking commanders: assistant chiefs Alfred J. Broadbent and Ronald Monroe, both 25-year veterans who had climbed the ranks.

Broadbent was in charge of special services, which includes most of the department's detectives and many of its specialized units. Monroe was a regional commander who oversaw the 2nd, 3rd and 4th districts.

Broadbent will become vice president of security at Amtrak. Monroe said he has not decided what he will do next.

Abraham Parks, a 31-year veteran, announced he was leaving his job as the 7th District commander to work with his son in a private business. Cmdr. Jeffrey Moore, a 30-year veteran in charge of the 2nd District, said he was retiring. He, too, said he hasn't decided what he will do in retirement.

While all the commanders said they were retiring so they could try something new, Parks said he was leaving also because he felt that Ramsey micromanaged the department and did not give commanders sufficient authority.

He pointed to what he called onerous, hours-long daily crime-trend meetings held at police headquarters. Often, commanders do not start working in their districts until after lunch, he said.

"It's difficult [when you don't] have hands-on quality time at your districts until after 1 p.m.," Parks said.

Ramsey "doesn't trust us and has made comments that he doesn't trust the captains and lieutenants to do the right things," Parks added.

Parks said morale among the rank-and-file and commanders was at its lowest since the late 1980s and early 1990s, a time of budget cuts and a high murder rate. Union officials also have cited low morale.

A half-dozen senior commanders, speaking on the condition of anonymity because they fear retaliation for criticizing police management, said they believe the department is top heavy.

"Some people may not agree with my methods," Ramsey said. But the results "speak for themselves," he added.

Union officials said the departures create a vacuum of experience in the top ranks.

"This is a huge loss of knowledge for the department," said Sgt. G.G. Neill, secretary of the D.C. police labor committee in the Fraternal Order of Police Lodge 1.

The departures have created a new corps of commanders east of the Anacostia River, where the police face some of their greatest challenges.

Robin Hoey, the former inspector in charge of the 3rd District substation, was promoted to commander of the 6th District. Joel Maupin, the inspector in charge of the 6th District substation, was promoted to commander of the 7th District.

Among the department's other changes:

* Winston Robinson, who was regional commander overseeing the 6th and 7th district commanders, was moved to Broadbent's slot.

* Willie Dandridge, former commander of the 6th District, was promoted to assistant chief and took Robinson's job.

* Peter Newsham, who had been assistant chief overseeing the Office of Professional Responsibility, took Monroe's job as regional operations commander in charge of the 2nd, 3rd and 4th districts.

* William Ponton, Ramsey's former chief of staff, was promoted to assistant chief and took Newsham's post.

* Alton Bigelow, a former captain, was promoted to inspector in charge of the 6th District substation.

* Andrew Solberg, a captain, was promoted to inspector in charge of the 1st District substation.

* Diane Groomes, a captain, was promoted to inspector in charge of the 3rd District substation.