The lawyer was unsure
The lawyer knew that Patricia and Mark lived in the house since about a decade. This made the timeline crucial. He struggled with the uncertainty of the age of the mysterious object.
Mark realized the gravity of the situation: If the team was able to collect evidence that the peculiar metal artifact was buried at that location around the time that Mark and Patricia had moved in, the scales could tip against him, putting him in serious danger. This timeline was crucial to the case, and stakes were high.
