Legal Question in Landlord & Tenant Law in Pennsylvania

Yes, I think you do. You occupied the premises. Technically, when you did this, the prior occupant's lease ended so you were not still on their lease. To the extent that one of the friend's skipped out, did you have a written agreement with him? The landlord already has advised you that the rent is owed and he does not care if it is paid by you, your other roommate or all 3 of you as long as it is paid. That means if one skips, the others are still on the hook. In such case, the remedy is to sue the friend, but only if you have something in writing. And you are going to be limited to the amount you can collect. A landlord or sub-landlord has a duty to find a new tenant. That means you would have to find a new roomie. At most, you could only sue the roo,mie who skipped for 2-3 months' rent. Anything more than that is not reasonable.