Play video content EXCLUSIVE DECEMBER 2018 TMZ.com

Jen Harley's convinced Ronnie Ortiz-Magro ransacked her home this week because there's video proof he destroyed her security camera a month ago during another violent incident no one knew about.

TMZ obtained this Dec. 4 Ring security footage showing Ronnie hauling back and smashing the camera at the front door of Jen's Las Vegas home. Law enforcement sources tell us the "Jersey Shore" star showed up around 10 PM that night and also threw an object through a window when she refused to let him inside. We're told she filed a police report, and Ron is a suspect for destruction of property.

The incident is highly relevant, considering Jen says someone broke into her house and trashed it on New Year's Eve after she and Ron got into a fight at a Vegas nightclub. Sources connected to Jen tell us these pics show the utter destruction that was left behind.

As you can see, someone went to town. The entire place looks like a complete mess ... there's a huge hole in a wall, shattered glass everywhere, toppled furniture, destroyed artwork, overturned tables, broken kitchenware, and a smashed flat-screen TV.

As we reported, Jen's blaming her baby daddy and he has been named a person of interest.

We also broke the story that Ronnie went to cops too ... claiming Jen hurled an ashtray at his head during their NYE nightclub clash.

Despite the Dec. 4 and NYE incidents ... Ronnie and Jen smiled and posed together for a family Christmas photo.