Baltimore Mayor Sheila A. Dixon was charged yesterday with 12 counts of felony theft, perjury, fraud and misconduct in office, becoming the city's first sitting mayor to be criminally indicted.

The case stems in part from at least $15,348 in gifts Dixon allegedly received from her former boyfriend, prominent city developer Ronald H. Lipscomb, while she was City Council president. She also is accused of using as much as $3,400 in gift cards, some donated to her office for distribution to "needy families," to purchase Best Buy electronics and other items for herself and her staff.

Lipscomb was not indicted in the Dixon case, but he and City Councilwoman Helen L. Holton were charged this week in a separate $12,500 bribery scheme. Both cases grew out of a nearly three-year probe by the state prosecutor into City Hall corruption.

The investigation has hung over Dixon, a Democrat, even as she became the city's first female mayor and oversaw a significant decrease in the city's homicide rate, reducing killings to a 20-year low. Viewed as an energetic and charismatic leader, she has earned praise from residents for implementing an easy-to-use recycling program and displaying a willingness to tackle the city's systemic racial and economic disparities.

It is unclear what the indictment will mean for the mayor. She has pledged to remain focused on her job, and many local officials rallied behind her yesterday. But even ceremonial events will take on new dimensions. Many wondered yesterday, for example, whether Dixon will appear with President-elect Barack Obama next week when he makes a planned stop in the city.

At a news conference yesterday at her attorney's office in Clipper Mill near Hampden, a composed Dixon said she was innocent.

"I will not let these charges deter me from keeping Baltimore on the path that we have set, or from carrying forward the significant progress we have made thus far," she said, reading a prepared statement. "I am being unfairly accused. Time will prove that I have done nothing wrong, and I am confident that I will be found innocent of these charges."

If convicted on all charges, the 55-year-old former teacher and mother of two could be sentenced to 85 years in prison. The most serious charges, two counts of felony theft, each carry a possible 15-year prison term.

Her attorney, Arnold M. Weiner, in a half-hour presentation carried live on local television and designed to win over the court of public opinion, accused those investigating the mayor of partisan motivations.

Weiner noted that State Prosecutor Robert A. Rohrbaugh and former U.S. Attorney Thomas M. DiBiagio, who investigated her earlier, were appointed by Republicans, and he accused Rohrbaugh of harboring an "obsession" in pursuing the mayor.

"There wasn't a bedsheet he did not look under or a lead he found too trivial to pursue personally," Weiner said.

The lawyer used courtroom exhibit-style poster boards to argue that Dixon did not perjure herself by failing to include the Lipscomb gifts on her city ethics forms, saying city code does not require disclosing gifts from subcontractors, such as Lipscomb.

Using a red pen, he pointed to a city code provision that requires the city's finance director to maintain a list of the companies doing business with the city. Weiner said that the city has not kept that list. Staff at the city's finance department could not be reached for comment by deadline.

Rohrbaugh declined to respond to questions, and prosecutors would not say whether their probe has ended. He said in a statement: "The public's trust in their elected officials is essential to the proper functioning of government."

The City Hall corruption probe dates to the fall of 2003, when federal authorities subpoenaed five years' worth of financial records from all City Council members. When that inquiry ended 18 months later with no charges filed, Weiner said, Rohrbaugh began an investigation of his own.

That state investigation eventually spanned as many as nine Baltimore grand juries. Weiner called it the longest and most expensive public corruption investigation he had ever seen.

In the end, a Baltimore Circuit Court grand jury that expired yesterday returned a 31-page indictment of the mayor.

One theft charge involves misconduct in December 2007, when Dixon was mayor. According to the indictment, a Baltimore housing employee purchased Toys "R" Us gift cards to be distributed to underprivileged children during a holiday event. Dixon allegedly gave one of those gift cards to a member of her staff, and five others were discovered at her West Baltimore house when investigators raided it in June.

Among other accusations: In 2004, 2005 and 2006, Dixon solicited gift cards - to Target, Best Buy, Old Navy and Circuit City - from two developers. She then used some of the cards to purchase a PlayStation2 controller, a PlayStation Portable, a Samsung digital camcorder and other items she either kept or gave to staff members as Christmas presents, the indictment said.