I'm getting confused about the letter was it something taken out of the mailbox and another letter put into the envelope. That makes sense to me. I thought it was mentioned that envelope addressing matched his handwriting. Or is it inconclusive? So confused lol.I don't think that the police were the intended audience of the letter. Maybe it was only meant for Debra; maybe the goal was to get her to calm down. Do you think that someone other than Tommy wrote the letter? I think that it's his handwriting, and the fact that the letter doesn't fit in the envelope removes all doubt.
If he wrote the note I don't think saying your wife ran off with two minor girls is every a good idea. If it was just his Rachel that would be different. It would still be questionable but it also wouldn't be crazy. A young wife leaving her husband but making sure her sister has a place to live and he isn't alone, believable (maybe??). If he wrote under those circumstances just to give family a peace of mind, not great, but he wouldn't be hurting any other families. If he wanted just for Debra why bother making it appear like the letter went through the postal service?