Mother Jones reported on this, saying that this audio was posted by @theanonmessage, a twitter account affiliated with Anonymous’ Operation Ferguson, a member of which I interviewed last night.
According to @theanonmessage, this recording contains audio excerpts from St. Louis County police dispatch over several hours on August 9, 2014, the day Michael Brown was shot and killed by a Ferguson police officer. The dispatcher starts talking about the Brown shooting around the 10-minute mark, while intermittently handling other calls. See below the recording for an updating list of interesting moments, with time stamps included.
9:35: “Ferguson is asking for assistance with crowd control . . .”
10:58: “Now they have a large group gathering there, she doesn’t know any further. . .”
11:20: “We just got another call stating it was an officer-involved shooting . . .”
11:30: “Be advised, this information came from the news . . .”
11:55: “We’re just getting information from the news and we just called Ferguson back again and they don’t know anything about it . . .”
20:00: “. . .destruction of property . . .”
21:55: “They are requesting more cars. Do you want me to send more of your cars?”
43:55: “Attention all cars, be advised that in reference to the call 2947 Canfield Drive, we are switching over to the riot channel at this time . . .”
Update, 4:40 p.m. ET: I tried to verify the dispatch recordings with St. Louis County Police but their media contact, Brian Shelman, did not answer the phone and his voicemail was full.
Update 2, 5:05 p.m. ET: Mashable is confirming that the St. Louis County Police Department is “aware of this and currently investigating.”
Update 3, 6:05 p.m. ET: A twitter follower of mine points out that the dispatch recording probably comes from Broadcastify, a database of public safety radio audio streams that’s available to anyone who pays for a subscription. It’s “far from a hack,” he says.