It concerns me that there is no tenants name. The rent mentioned, is that weekly, monthly or annually? Additionally, I would assume that there is no entry condition report. As others have mentioned, being a good tenant, may indicate a good one going forward. Is it possible that the seller gave the tenant an incentive to "present" well while we sell. All this could have occurred before the agent visited the place, so even their view may be a very limited one.
What level of risk are you comfortable with. Get advice, perhaps from another local agent about your possible liabilities.