It started with a photo, an unfounded assertion and an uncheckable fact.
The photo — of a tricked-out minivan — was posted by Claycord.com, a local news site for the East Bay San Francisco suburbs of Clayton and Concord. The thing looked to me like one of Google’s street-mapping cars, only bigger.
The assertion — that it’s a self-driving car — was made by Rob Enderle, a TV-friendly pundit who has made a career of being wrong about Apple.
The uncheckable fact — that the van was rented out to Apple — came from KPIX TV, the local CBS affiliate. It’s uncheckable because motor vehicle departments don’t release that kind of information, even to a private investigator, without a legitimate reason. (I know, I’ve tried.)
From there, Business Insider ran with it.
- There’s a mysterious Apple van driving around San Francisco
- It turns out those cameras on top of the mystery Apple van COULD be used for a self driving car
- Apple employee: We’re working on something that will ‘give Tesla a run for its money’
- RUMOR: Apple has poached a bunch of people from Tesla, and it IS making a car
When Henry Blodget‘s news organization labels as “rumor” a story built on a tissue of speculation they themselves have been spinning, journalists should tread carefully. I’m surprised John Gruber touched it.
My take: Don’t hold your breath.
Follow Philip Elmer-DeWitt on Twitter at @philiped. Read his Apple AAPL coverage at fortune.com/ped or subscribe via his RSS feed.