Is following a customer and photographing them okay if you think they’re stealing?

Edit: I am not an employee. Just someone wanting to know if this is standard protocol, and if not, what policy was violated.

A Lowe’s assistant store manager followed someone I know out in to the parking lot and was witnessed taking photos/video of them and their vehicle. When asked if there was a problem, the assistant store manager stated “the problem is that you didn’t pay for that.” The items were paid for, and the assistant store manager refused to look at the proof of purchase. Is this normal practice?