How do you prove urine odor to keep security deposit?

[Daniel Alfandre]

A tenant just moved out of my rental property and there is a urine odor throughout the first floor.  The floors are vinyl planks (Allure Trafficmaster).  She had a cat and signed a pet addendum that obligates her to pay to remediate pet odors.  However, during our move-out inspection, she claimed she cleaned up after her cat and that she doesn't smell any odors.  I don't see any apparent stains on the floors or walls that reveal urine but the odor is definitely there.   How would you handle this situation?