DAng. Hope she was not assulted. Its not uncommon for women to deny/hide/just want it to "go away". Hopefully she is getting some support, people with her who "enpower" her. Normally don't care for such terms but it does apply here. Give her as much control as possible. (realizing there are other concerns)
If store has panic button I hope they train all employees to use them in any case. If its a legit Officer they should have no issue dealing with city Police.
@ 20 yrs ago I put on gas in small town station. Went inside and NOBODY. I checked office (unlocked) bathrooms, storage room, even cooler. (while loudly calling for anyone)
The till had a key in it. (so I assume I could have rang up sale) Instead I grab pen/paper/ Write "X gallons at $$ total X$$" and put cash for that amont under mat on till.
Pre cell phone days.