Jill claims the woman proceeded to beat her mercilessly ... causing a concussion and a severe back injury.
Janice Dickinson has been sued for allegedly beating the crap out of another woman in front of an elementary school last month ... only there's one little problem, cops say Janice was NEVER THERE!
A woman named Jill Gatsby claims she was trying to pick up her 5-year-old kid from an L.A. elementary school on September 28 ... but when she couldn't find a parking spot, she moved some trash cans in front of a nearby home from the street onto the sidewalk to make room for her car.
That's when Gatsby claims "a lady" came out of the home ... and became aggressive. Gatsby claims she whipped out her cell phone to record the incident, but "the lady" snatched the phone out of her hand ... and smacked her in the face with it.
Here's the rub -- Jill claims in her lawsuit that she had no idea who "the lady" was at the time of the attack ... and only determined her to be Janice Dickinson after conducting "an Internet search."
But law enforcement sources tell TMZ ... there is "no evidence" that Dickinson was involved and she is not a suspect.
TMZ also spoke with Janice ... who tells us, "In no way shape or form was I present during this alleged altercation."