Baltimore Mayor Sheila Dixon could have two separate criminal trials, defense attorneys announced yesterday, saying that the theft and perjury indictments will not be combined.

Dixon's defense attorney, Arnold M. Weiner, would not say why the trials will be separated and called the announcement "everyone's decision." State Prosecutor Robert A. Rohrbaugh said the decision rested with the defense and would not affect the way he tries the cases.

Dixon's trial on charges that she stole gift cards from needy families will go forward on Nov. 9. No date has been set for the perjury trial.

One reason to hold two trials instead of one is to prevent a "spillover effect" said Steve H. Levin, a former federal prosecutor who has his own defense firm. If a defendant is charged with multiple crimes, jurors sometimes are more likely to convict because they believe "if he is alleged to do all this, he must have done something," Levin said.

Also, Levin said that splitting the cases could give defense attorneys momentum if they secure an acquittal on the first one. "Pre-trial publicity is not always bad," he said. "If Dixon is acquitted in the first case, the prospective jurors will know the state prosecutors put on a weak case."

The announcement came after a hearing in which Weiner asked Judge Dennis M. Sweeney to dismiss the two perjury indictments that the mayor faces. Sweeney dismissed similar charges earlier this year saying that prosecutors used evidence that violated her legislative immunity when they asked a grand jury to indict her. Now Sweeney will have to rule on how broadly that immunity is defined.

The perjury charges stem from gifts Dixon received from her then-boyfriend, Ronald H. Lipscomb, a developer who at the time was seeking tax credits from the city. Elected officials are required to report gifts from anyone doing business with the city, and Dixon, who was then City Council president, failed to report on her city ethics forms that he gave her thousands of dollars in cash, paid for designer clothes and furs and funded trips to New York, Chicago and Aspen, Colo.

The state initially used evidence of Dixon's votes on those tax credits as evidence that she knew Lipscomb was doing business with the city and his gifts therefore should have triggered disclosure. But Sweeney ruled that a lawmaker's votes are protected by legislative immunity and cannot be used to prove Dixon knew about Lipscomb's city work.

Prosecutors re-indicted the mayor, this time showing that Dixon was aware of Lipscomb's business with the city because she attended a ground-breaking ceremony for one of the projects, attended numerous meetings about the projects and was quoted in a Baltimore Sun article saying she "twisted some arms" to help Lipscomb secure aid for a project.

Rohrbaugh said Dixon's lawyers "want to take a broad brush and say that almost everything Ms. Dixon does is subject to immunity." He said that Dixon's political acts, like a ground-breaking, should be distinguished from her legislative ones. "Only Ms. Dixon seriously contends that her political activities are covered by her legislative immunity."

Weiner argued Wednesday morning that the prosecutors made the same error when they re-indicted Dixon because they relied on what defense lawyers call privileged acts to make their case. "That raises a legitimate question," Weiner said during his hourlong argument. "Why would a prosecutor be so reckless as to again play with the same fire that burned him once?"

Sweeney said he will rule on the issue "as quickly as possible."