Suspicious vehicle parked at end of driveway

I have a female party on the phone with me right now.

Said a vehicle's been sitting at the end of her driveway, car is running.

She hasn't seen them get out or move or anything, but she is watching them on one of her security cameras and is a little concerned because she does have an HRO in place with somebody, but she doesn't know if it's them or not.