I'd be careful about talking to journalists at all, and default to not doing it. People writing about these murders have an incentive to make the Bay Area rationalist community sound bizarre, depraved, or salacious, and I'm sure some of them won't hesitate. Like the cops, journalists know how to make you feel like they're your best opportunity to get justice, and some will use that to get you to let down your guard. "Off the record" is not a legally binding agreement, and even if they don't attribute your quote, they can still twist it to make it sound like someone told them something sinister. It's tempting to try to set the record straight! But unless you're skilled in managing the media or have a reason to trust the specific person you're talking to (and a way to verify their identity), I'd steer clear. 

In the corporate / government world, the standard is to have one informed, skilled person whose job it is to interface with media, and everyone else's job is to direct the media to that person. Is there someone in the community who wants to take that role?