Buying a tenanted property-gamble?

Thinking of buying a repo property that failed to sell at auction. Price is 40-50% below market value.
It is tenanted, but they are unco-operative and there is no info about the type of tenancy they have available according to auction house.
Nobody has been inside the house, no viewings at all.
Unknown if tenants are even paying their rent.

Too risky, or worth a punt?