Negligent claim - warranty deed vs closing date

[Nic S.]

I fully intend to get a lawyer involved if it gets to that point but I figured I would see what you all think of this situation. 

My property manager received a letter from a current tenant stating on June 1, 2020 her child was shocked while plugging a cell phone into a wall outlet. Attorney is asking to be put in touch with my insurance carrier and if we don't comply they intend to file a civil suit under a claim of owner negligence. 

The letter states the incident took place on June 1st. I closed on the property June 3rd and had no prior knowledge of any electrical issues. The Warranty Deed has a date of June 1st and a recorded date of June 8th. 

My question is; what event signifies when is legal liability is transferred from seller to buyer? Closing docs or warranty deed? Thank you very much!