Can I file a Lien on a property that is for closed on?

Installed a building on February 25th 2020. The customer owes a balance and we have reached out numerous times. We have received notice that the property owner died by getting his death certificate. We tried to repo the building but it has electric hooked up to it. The Property is Managment by Guardian Asset out of Pennsylvania. Can you tell me if I can file a lien on this property?