'Jersey Shore' Star Ronnie Left Trail of Blood in Car Dragging Incide

Ronnie Ortiz-Magro left a mess behind after his baby mama allegedly dragged him with a car ... and TMZ has some bloody shots of the vehicle.

In the photos, blood streaks can be seen on the outside of the ride we're told Jen Harley was driving when she and the 'Jersey Shore' star got into a fight Sunday coming home from a Vegas BBQ. You'll recall ... Jen allegedly hit Ronnie in the face, then dragged him when he tried to get out.

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As you can see ... the vehicle also suffered a flat tire, which we're told was the result of Jen driving over the median when she took off ... with their 2-month-old daughter, Ariana, in the car.

There's also a shot of the interior console covered with blood ... possibly from Ronnie's injuries after being struck in the face.

Harley was arrested for domestic battery and booked at the Clark County Detention Center. She was also the suspect in a battery investigation for allegedly spitting on and hitting Ronnie 3 weeks ago during another argument.

We broke the story ... Ronnie's friends fear for his safety if he goes back with Jen, and are equally concerned about the well-being of their daughter.