Orange County – from www.tmz.com – Cops just swarmed in on Jesse James’ ex-wife Janine Lindemulder after she unloaded on a paparazzo … outside of the courthouse in Orange County.

It all went down as Janine was entering court for a child custody hearing — as several photogs followed her and snapped pics.

But it all came to a violent head once Janine got into an elevator — and one photog got too close. Janine — who was holding a warm drink in her hand — swung at the photog, dousing him in liquid .. and sending him reeling backwards into a wall.

O.C. Sheriff’s deputies moved in — and are currently questioning Janine about the incident. The photog is on the way to the hospital.