The round blood drops, which reveal the time of the murder.
Ralston claimed that when Lauren left the gas station, the wind was blowing hard. But the round blood drops under the body indicate that no wind had been blowing when the fence post bashed in Lauren’s head. This told the officer two things. (1) It was no storm-related accident. (2) Ralston lied.
Ralston North eventually confessed. That day at the station, Lauren told him the truth about her affair with Teddy and their intention to run away. Ralston was also in love with Lauren and this revelation sent him over the edge. He screamed and threatened her and Lauren went running for her life, hoping to reach the safety of Teddy’s arms. Ralston caught up with her, pulled a post from the ground and bashed in her head. A short time later, when the storm arrived, Ralston changed his story so it would seem as though Lauren had left during the windstorm and simply had an accident.