Friend steals, can't forgive, talk to mom?

[Johnsmith1003]

In a nutshell

 

Good childhood friend and I were close. He moved away, then came back to live with me and my parents for a year and a half. Sometime around March 2010 his dad who he isn't close to and his step sister moved in with us (both in the garage). About a month or two in, the step sister snuck into my room thinking I was asleep, grabbed my wallet, and subsequently took out $500 of my money through my ATM (they somehow had my PIN). I noticed, contacted BoA to check the cameras. They said the perp covered the camera up so it was out of their hands. When I got suspicious of the step sister and father, she springs a false 'rape' report on him and the cops come to take him away, while I regretfully drove her to the police station, knowing full well it was a cop out to get out of stealing from me and being caught. My best friend stayed with me still, but seem unmoved and careless to the whole ordeal, which led me to believe he was in on it, or knew, or just didn't care at all. He eventually moves back and I get a check in the mail from his car crash settlement, I contacted him saying he needs to make it right and pay me my $500 that his family stole. He took blame for it easily (which pushed the fact he may have known further) but once I mailed it he severed contact with me of course.

 

Now I keep thinking of it the past week and thinking I should contact his mom through FB (she was the protective kind, but fair and thought of me as her other son so it wouldn't be too weird) and ask her if she could shed some light on it. I just cannot let it go! Should I contact her or just leave it be? Sorry for the rant.