The new era at Miami City Hall opened with a double dose of change Wednesday, with Police Chief John Timoney resigning before the swearing in for the new mayor who sought his ouster: Tomás Regalado.

The chief's announcement meant that Regalado had cemented the first promise of his administration: removing the hard-nosed former top cop in Philadelphia who was credited with turning around a dysfunctional department in his seven years in Miami.

``Everywhere John Timoney has been -- New York, Philadelphia and now Miami -- he has left a better place for cops and citizens alike,'' said Chuck Wexler, executive director of the Police Executive Research Forum, of which Timoney is president.

``Many think of Timoney as a tough Irish cop, but those of us who have come to know John regard him as one of the most thoughtful people in policing,'' Wexler said.

Regalado had a different view, agreeing with police union leaders who say employee morale had sunk under Timoney's tenure and that change had to come.

Already, names are being weighed to replace Timoney when he retires Jan. 15: Assistant Chief Adam Burden; Maj. Miguel Exposito, who oversees the property section; and Maj. Manuel Orosa, over the criminal investigations section.

But sources told The Miami Herald that Regalado is most likely to lean toward Exposito, a 35-year veteran with long ties to the mayor.

In his retirement letter dated Tuesday, Timoney gave no indication of what he might do next, but instead cited internal reforms and reduced police shootings.

The department had grown ``not only in the number of officers, but also in resources, prestige and the respect it deserves,'' he wrote.

City Manager Pete Hernandez said the chief will remain through early next year to ensure a ``smooth transition.'' A compensation package has not been worked out for Timoney, 61, who did not respond to interview requests Wednesday.

Timoney's pending departure added a sense of urgency to Regalado's noon swearing-in as Miami's 33rd mayor.

Moments after he was sworn in, Regalado, mobbed by reporters in a packed City Hall, said he'd announce a replacement next week.

``We need a new strategy and better morale for the troops,'' Regalado said.

As dignitaries including Gov. Charlie Crist and fellow U.S. Senate hopeful Kendrick Meek and hundreds of supporters packed the chambers, hundreds of others watched the proceeding outside from under a tent, while eating paella and dancing to live merengue music.

When word spread of the chief's retirement, it briefly stole the spotlight from Regalado's big day. Commissioners attending the event feigned surprise at the announcement -- and had differing reactions to it.

Commissioner Marc Sarnoff said Timoney did a ``great job,'' but that ``change can be good, too.''

Michelle Spence-Jones, who a few weeks earlier scolded the department for arriving late at an Overtown shooting, said ``leadership in some places just did not serve my district.''

Timoney was not in attendance Wednesday. But Tuesday night, he was calm and friendly at a book-signing reception for Gerald Posner's Miami Babylon on the rooftop terrace of a Collins Avenue hotel. Dressed in civilian attire, he smiled and said little.

Former Mayor Manny Diaz brought Timoney to Miami after a national search in 2002. Timoney had developed a national profile during his days as the second in command of the NYPD and then Philadelphia police commissioner.

Diaz said his first order as mayor was to restore order to a police department that had far too many shootings and several officers being tried for misconduct.

The day Timoney was sworn in, a federal corruption trial started against 11 officers.

He was the first outsider to lead the department in decades, and quickly changed policies. The department, which had been criticized as trigger happy, went 20 months without an officer firing a weapon. Tasers in some cases have replaced guns. Police dog bites and crime are down.

Howard Simon, executive director of the American Civil Liberties Union of Florida, gave Timoney a mixed review.

``I think he was precisely what the Miami Police Department needed at that time,'' Simon said, saying he set a ``new tone'' for the department.

Still, Simon pointed to the handling of the 2003 Free Trade Area of the Americas Conference in Miami as a case in which police went over the line while clashing with protesters.

Critics say the police were abusive. Hundreds of protesters were arrested, and the city has since settled six lawsuits for more than $500,000. The ACLU filed most of the suits.

``His record on civil liberties is an enigma,'' Simon said. ``There are some very good things and there are failures. The good things are what he did to change the tone and shootings of unarmed civilians and what he's done in regards to police and immigration law.

``What he has done that are failures are the Miami model in regard to the FTAA and his resistance to civilian oversight in law enforcement.''

Timoney has also bumped heads with the union.

In 2007, the union leaked a story that Timoney was driving a free Lexus SUV from a South Florida car dealer. Timoney denied the accusation at first, then paid for the vehicle, and eventually paid $1,000 in fines to the state and county. The city manager docked his pay for a week.

The union also contended that city crime statistics were being fudged. The FBI and Florida Department of Law Enforcement took a look -- but found no evidence of statistic suppression. A short time later, the union overwhelmingly dealt a vote of no confidence for the chief and Deputy Chief Frank Fernandez.

Armando Aguilar, the Fraternal Order of Police president, called his departure ``long overdue.'' In a slap at Timoney, he said he hopes the next chief ``respects the troops.''

Now, attention turns to the potential successor, Exposito, who led the department's Internal Affairs division during its most trying time.

As a captain in 2000, Exposito filed a whistle-blower complaint with the city's Civil Service Board over what he said was an unfair demotion. He argued he was demoted from being a major after complaining about alleged dossiers of elected officials being kept by the police department.

He also said his rank was lowered because he supported bringing in the FBI to investigate a police gun-planting incident in Coconut Grove in 1997. In that case, police shot a homeless man near CocoWalk when he pulled out a transistor radio they thought was a gun.

In 2002, Exposito reached a settlement with the city.

That same year, the controversy over dossiers on elected officials erupted again. This time, Exposito stood before commissioners at the request of Regalado, explaining how Mayor Joe Carollo -- a Regalado foe -- had known the police department kept dossiers on elected officials.

Carollo questioned why Regalado paraded Exposito ``in this political circus atmosphere,'' instead of notifying the Florida Department of Law Enforcement.

Exposito was promoted once again to major under Timoney.