White Motercycle keeps pulling into our driveway and turning around, and a White Car too.?

Disclaimer: No one in my family owns a White Motercycle (or a White Car).

The house I'm currently living in was vacant for 6 years (we would occasionally sleep in the house on certain weekends), and my family and I believe that this person/these people has/have been pulling into the driveway during the 6 year vacancy. This happened again today. It happened about a month ago on a Saturday (I saw them pull out). And a White car pulled into the driveway on my birthday as we were about to walk back into the house. Do you believe this person (or these people) is/are trying to break in, or commit any other crimes on our property? Also, someone parked a stolen car in the driveway not long before we moved in. Should we call the police, or just keep watch on this person/these people?