AVault has published a story about the lawsuit being brought by the parents of victims in the 1997 Kentucky high school tragedy (see story), featuring court documents they've obtained that shed some light on what companies are being mentioned. Here's an excerpt:

According to court documents obtained by the Adrenaline Vault, the defendants include Apogee Software, id Software, GT Interactive, Sega of America, Atari Corporation, Acclaim Entertainment, Interplay Productions, Midway Home Entertainment, Nintendo of America, Activision, Sony Computer Entertainment, Capcom Entertainment, Eidos Interactive and Squaresoft. The complaint contends these companies produced and supplied games that made the violence “pleasurable and attractive” and disconnected the savageness from natural consequences. In addition, the plaintiffs claim the games taught Carneal to point and shoot in a fashion that made him an “extraordinarily effective killer.”

I contacted id Software's Todd Hollenshead for a clarification, and he did tell me that they have not been served with a lawsuit as of yet, but mentioned that if that happens he won't be able to speak about pending litigation. We'll keep you updated as this develops...