Family members of some of the 12 people shot to death during a midnight movie showing in Colorado plan to go public Tuesday about some behind-the-scenes events they say need to be discussed.

The families have not said what those events were. They said in a statement that they would "speak with one voice" for the benefit of all the victims.

Anita Busch, a spokeswoman for the group, declined to elaborate on the topics.

Busch said she expects the families of most of the 12 people killed in the shootings to be represented.

The suspect in the July 20 shootings, 24-year-old James Eagan Holmes, faces charges of murder and attempted murder.

Police say Holmes was heavily armed and wearing body armor and a gas mask when he opened fire on the audience in a packed theater in the Denver suburb of Aurora during a showing of the latest Batman movie.

In addition to the 12 killed, 58 were injured.

Holmes is being held without bail and has not entered a plea. Defense lawyers have said he is mentally ill.

Holmes was a first-year Ph.D. student in a neuroscience program at the University of Colorado, Denver. He 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. Fenton is expected to testify at a hearing Thursday.

Defense lawyers are fighting prosecution attempts to see the material.

Investigators, attorneys on both sides and the university have said little about the case 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.