The case management statement also describes what happened when Pianta and Sheehan arrived at the jail's booking desk:

Plaintiff was initially compliant during the booking process. However, her demeanor changed and she threw a hair tie at Officer Pianta which struck the officer. Inexplicably, plaintiff then began looking through her purse and refused the officer’s instructions to stop doing so. Plaintiff attempted to pull the purse away from him. Officer Pianta then placed plaintiff in an arm bar control hold to gain compliance. Plaintiff began resisting and attempted to punch the officer. Acting in self-defense, the officer used an arm bar takedown and guided plaintiff to the ground. Moments later the officer observed blood coming from plaintiff’s facial area and medical assistance was requested. ...

For what it's worth, that account seems to soften what Pianta wrote in his police report of the incident, which described the takedown of Sheehan as a response to her "violently punching with a closed fist at my face." He also describes using an "arm-bar" technique to "guide her to the ground." So, you get a couple of clear impressions: An officer was reacting to a persistent physical threat, and he exercised care in "guiding" the plaintiff to gain control of the subject.

As it happens, the scene was recorded from several angles and devices, including officers' body cameras and jail security video.

No two people will see these videos precisely the same way. But it's awfully hard to square Pianta's and BART's account with what the cameras captured. Yes, Sheehan was noncompliant. Did she pose a threat? That's not evident. The contention that Pianta "guided" Sheehan to the ground? Well, we can let the list of her injuries, inventoried at Eden Hospital and reported in the case management statement, speak to that claim:

Principal problem:

Active Problems:

Loss of consciousness

Fracture: Left maxillary depressed comminuted anterior wall, nondisplaced medial wall, displaced lateral wall

Left orbital wall lateral displaced comminuted fracture

Fracture: medial wall right maxillary antrum

Concussion with brief loss of consciousness

Eyelid laceration

Lip laceration

Less clinically, part of Sheehan's face was shattered.

The video of the incident is sickening -- an impression reinforced by the involuntary gasps of witnesses. Stated simply: Pianta slams Sheehan face first into the floor. You can hear a gruesome crack as she hits. There's no evidence he attempted to "guide" or control Sheehan as he propelled her downward.

How to explain such a use of force? Sheehan's attorney, John Houston Scott of San Francisco, told ABC7: "She was uncooperative. She was intoxicated. And I believe she had to be taught a lesson. In police jargon, she flunked the attitude test."

It appears that what happened to Sheehan caused barely a ripple inside BART itself. A spokesman for the agency says BART Police Chief Kenton Rainey reviewed and "signed off" on a report on the episode. Pianta was never placed on administrative leave, the agency says, and remains on the job. However, the lawsuit over the assault -- it's hard to call it anything else -- has apparently prompted some action: both BART police internal affairs investigators and the department's independent police auditor are conducting inquiries.

Sheehan has asked for a jury to hear the suit, which alleges Pianta used excessive force and violated her constitutional rights. It's hard to see that happening, given the video evidence. BART and other defendants will presumably settle rather than open the way to endless replays of Sheehan being brutalized.

But that won't end the matter. BART will still need to make a public accounting for how it's handling the case of an officer whose own account of his actions appears to differ so wildly from what the video shows.

Post updated to include details of BART's handling of Sheehan case to date.