I received a call from this number and the caller left a voice mail. It was from the Arapahoe County District Attorney's office - Victim Advocate Unit (I was a victim of a crime). Not sure why the caller ID was all zeros, unless they blocked their number.
Just got a call from 720-000-0000 at 12:47am. I freaked out because it was so late, and hung up on the call without answering. Whoever or whatever it was did not leave a voicemail. What the heck kind of phone number is that anyway?