In George's frame of reference, a bolt of lightning strikes at $(t_1,x_1) = (12,17)$ and, subsequently, an explosion happens at $(t_2,x_2) = (18,26)$. George claims that the lightning caused the explosion, but Gracie disagrees. Could George be right? (Assume we are working in units with $c = 1$).

In George's frame of reference, a bolt of lightning strikes at $(t_1,x_1)=(12,17)$ and, subsequently, an explosion happens at $(t_2,x_2)=(21,25)$. George claims that the lightning caused the explosion, but Gracie disagrees. Could George be right? (Assume we are working in units with $c=1$).