Washington DC TOPA for formal rental

[Tim Burke]

I own a single condominium unit in Washington DC that I previously lived in. Last year, I moved out of state to take a new job and turned the condo into a rental. My tenants gave me notice that they needed to move out at the end of their lease, and we signed a Notice to Vacate and all that jazz, and now the tenants have moved out. 

As a result of the tenants leaving, I decided to sell the condo, which is currently on the market. I have an agent for a potential buyer asking why I did not serve TOPA (Tenant Opportunity to Purchase Act) notices to my tenant and now it may be holding up the offer process.

As far as I understand the law, I would only have to offer the property to my tenants if I was selling it while they were still there, and since they have moved out (and out of the state) of their own accord, it was not necessary to offer to sell the property to my now former tenants.  

Anyone in the DC metro area able to chime in on this?