AURORA, Colo.—Relatives of some of the people killed in the Colorado theater shootings are holding a news conference to talk about unspecified events they say need to be addressed.

The news conference is scheduled for Tuesday.

A news release says the families will talk about some behind-the-scenes events that they believe need to be discussed. Anita Busch, a spokeswoman for the group, declined to elaborate.

Twelve people were killed and 58 injured when a gunman opened fire on July 20 during midnight showing of the latest Batman movie in the Denver suburb of Aurora.

James Eagan Holmes faces charges of murder and attempted murder. He’s being held without bail and hasn’t entered a plea.

His defense lawyers have said he is mentally ill.