Prosecutors may file a third HIV-related charge against a Lawrence man already charged with knowingly exposing two women to the virus through sexual activity.

Robert W. Richardson III, 29, made a brief appearance Tuesday in District Court and was scheduled to have a preliminary hearing where witnesses would testify. But his attorney, Thomas Johnson, asked for a postponement, saying that he had been told prosecutors were considering filing a charge involving a third victim.

Johnson asked that the two cases his client already faces be combined for the preliminary hearing. Judge Stephen Six rescheduled it for May 2.