Dr. Lesse and the police: he was embarrassed, ashamed,
frightened didn't want his father to know, didn't want
her mother to know--etc. But this motive would kick in
only after Tommy knew Martha had been murdered. Only
after finding out that something profoundly unsavory
had befallen her directly after their sexual encounter
would Tommy be able to feel a reactionary, irrational
associate guilt and actively want to conceal their
mutual masturbation incident out of innocent
If Tommy knew nothing about Martha's murder why, when Julie came into his room at 1:30 am, would he lie to her about hanging out with Martha? Was it really that big a deal? Why did he begin his pattern of deception at that point? This is assuming that when Tommy told Julie "the back door" he meant the side of the house at 9:30--which is what we would soon tell the investigators. However, there is a chance Tommy meant "the back door" as literally in the back of the house. If he didn't mention a time to Julie, than [WW] he wasn't exactly lying, only neglecting to be entirely honest. Which, perhaps, is understandable. There are serious reasons Tommy wouldn't necessarily want to announce to his big sister he had been rolling around with fifteen year-old Martha Moxley. Yes, but why did he mention the test to her? The test is nothing but a complete and calculated fiction. If we can't be certain that Tommy is lying about where he last saw Martha, we at least definitely know he is lying to Julie about why.
Before we leave this point, there is evidence which suggests that Tommy was lying to Julie about where and when he last saw Martha. From her interview under [^] with John Gaspar on 3/5/93:
Gaspar: What is Mrs. Moxley's first name?
Julie: I don't know. She was asking where Martha is, please go ask Tommy if he knows where she is. So, I went up to the third floor, woke Tommy up and he said the last time I saw her was at the back door when they said goodnight--which is a whole scenario I left out actually.
Gaspar: Well, you told me a bunch of people were by the side of the door.
Julie: But this was after dinner while I was sitting in the car waiting for Andrea to go back up to the house to get the keys. I could hear Tommy and Martha at the back door, saying good-night and Tommy saying, "I've got to go."
Gaspar: And where did Tommy go?
Julie: I could see him, because of where my car was parked, close the back door, walk through the kitchen...
Gaspar: You could actually see someone walking in the kitchen, from window to window...
Julie: Yeah. By the time Andrea got to the front door, which was locked, or she couldn't get it open, Tommy met Andrea at the front door and got the keys, they chit-chatted, I'm, guessing maybe a minute.