@Jenny1226 I don't quite understand, either. The previous owner should have delisted the property when they sold it to you. The only way that reviews for the property from guests you have hosted could appear on his account is if those guests booked through his account and he turned over those bookings to you when the place became yours. If that's what happened, you did it wrong, and there is nothing you can do now about getting those reviews on your account.
What should have happened was that when the previous owner sold the property, he should have gotten in touch with all the already booked guests, explained that there was a new owner/host, and asked if they wanted to keep the booking, or cancel with full refund. If they still wanted to keep the booking, then it would have been a matter of Airbnb facilitating getting those bookings transferred to your new listing and removing them from the listing that was being deactivated.
The previous owner needs to deactivate that listing ASAP or you are just going to have more problems.