Relatives of some of the people killed in the Colorado movie theater shootings plan to speak publicly Tuesday about unspecified events that they say need to be addressed. They have scheduled a news conference to discuss behind-the-scenes developments and will "speak with one voice" for the benefit of all the victims, they said in a news release. The release did not elaborate on the events they plan to discuss. Anita Busch, a spokeswoman for the group, declined to comment on the topics. Busch said she expects the families of most of the 12 people killed in the shootings to be represented. A heavily armed gunman wearing body armor and a gas mask opened fire on July 20 in a packed theater in the Denver suburb of Aurora during a midnight showing of the latest Batman movie. In addition to the 12 killed, 58 were injured. Charges against the suspect, James Eagan Holmes, 24, include murder and attempted murder. He is being held without bail and has not entered a plea. Holmes was a first-year Ph.D. student in a neuroscience program at the University of Colorado, Denver, but told university officials about six weeks before the shootings that he was withdrawing. Prosecutors have said Holmes failed an oral board exam June 7, at about the same time he began buying weapons and ammunition. Prosecutors are seeking the university's records on Holmes and also want to see a notebook that Holmes reportedly sent to university psychiatrist Lynne Fenton. His defense lawyers have said he is mentally ill. They are fighting prosecution attempts to see his school records and the notebook. Fenton is expected to testify at a hearing Thursday. The families' announcement added to the sense of mystery that has surrounded the case since its early days. Investigators, attorneys on both sides and the university have said little outside court hearings, citing a gag order imposed by Arapahoe County District Judge William Sylvester. Many court documents have been kept secret as well. Only a handful of family members of the slain victims have spoken publicly, and most of their comments came in the first few days after the shooting. A joint appearance by multiple families would be a first in the case.