Depends. After the original walk through, did the tenants get anything in writing regarding the condition of the property after they moved out. I would strongly suggest that you hire a local attorney that specializes in real estate. It sounds like you may need a letter written by an attorney to defend your interest.
I think I understand the issue. Under ARS 33-1321, the landlord must provide an accounting within 14 days of termination of the tenancy regarding damages to the premises and where she has applied the security deposit. Thus, she will not be able to make a claim against the first tenants. Also, if the damages existed before tenants moved in, tenants are not responsible for them. She cannot simply sue each of the tenants and say, in essence, 'you figure out who did the damage.' She bears the burden of proof that the tenant she sued is responsible for the damages.
No one should rely upon generalized information for their specific matter unless they have consulted with a qualified professional specific to their matter. This is not intended to be used as legal advice to persons who have not retained my services in writing.