When she ran Tony down in Megan's driveway, it was suspected that Tricia had gone over the edge and intentionally killed him, whether this was true or not was never revealed.
Tricia had gone over the edge. This was what it was suspected. Tricia intentionally killed him. This was what it was suspected. This was true. Tricia was never revealed. This was what it was suspected. She ran Tony down in Megan's driveway.