Mayor Byron W. Brown is facing criticism for demoting two popular police chiefs and, in one instance, replacing her with a lieutenant who has been protecting the mayor since 2008.

Brian K. Patterson has become the new chief in the Central District, a station that patrols downtown and many other neighborhoods. He replaces Donna M. Berry, who has returned to her lieutenant’s post after heading the station for four years.

Patterson has been frequently seen with the mayor at scores of events, often driving Brown to various destinations. But administration officials bristled at claims that Patterson’s role was largely that of a mayoral chauffeur.

In a written statement, Brown described Patterson as head of the city’s “dignitary protection services since 2008, coordinating all security and threat assessment issues with federal, state and local dignitary protection divisions.”

The administration also noted that Patterson has been on the police force for 14 years and has experience working in the Central Station.

“I’m surprised that Donna Berry was demoted, because I always thought she did a very good job,” said Common Council Member Michael J. LoCurto, whose Delaware District has several neighborhoods that are served by the station. “It’s definitely odd that she was demoted.”

Meanwhile, the president of a citywide coalition of block clubs said she is bitterly disappointed that the mayor has demoted South District Police Chief Brian S. Strobele. Brown has named Patrick M. Pascall chief. Linda J. Freidenberg, president of the Board of Block Clubs, called Strobele’s demotion “a big mistake” and “a few steps backward in the development of good crime-prevention practices in Buffalo.” Strobele returned to his lieutenant’s post.

“Every block club in South Buffalo loved him,” Freidenberg told The Buffalo News. “He went out of his way to help us.”

While Freidenberg doesn’t know Pascall, she said, she believes that the mayor should have followed the adage, “If it ain’t broke, don’t fix it.”

Unlike commissioners who must be confirmed by the Council, the mayor has the power to appoint police chiefs. Given this reality, said Council President David

A. Franczyk, he can’t criticize Brown for the appointments.

Some sources within the police rank-and- file have speculated that the changes were made for political reasons.

“My guess is that politics almost always plays some role in these kind of decisions,” Franczyk said.

When Brown announced the changes at a Tuesday news conference, he did not elaborate on why he made them.

“We’re going to be going in another direction with a couple of the managers in our department,” was all Brown would say. But the mayor has yet to name a permanent police commissioner. Daniel Derenda has been running the department on an interim basis since January.

Wouldn’t it have made sense for the mayor to get input from a permanent commissioner before making changes at the top of two of Buffalo’s five police districts?

Peter K. Cutler, Brown’s chief spokesman, said the administration had no further comment on the issue.