The mother of Mason, 4, and Penelope Disick, 19 months, was robbed of $50,000 in cash from her home last month.
"It's so sad," the source tells Us. "She feels so violated and is freaked out."
TMZ reports that Kardashian, 34, believe the stolen money was done as an inside job. Kourtney's sister Khloe Kardashian recently discovered that $250,000 of jewelry was missing from her home and the police believe that the two thefts were connected.