There's a difference between drug "rehab" programs as we know them, and AA. The term "rehab" didn't even enter the lexicon until the 70s or so, way after this guy was imprisoned. And anyway, it stretches credulity to believe that this guy wasn't doing drugs while in prison.
The guy should still be locked up as far as I am concerned, but don't knock people stopping using dope. There are the ones who do anything to look good for parole, privilleges etc, but I do know some who actually stop and stay quit because it is a problem rather than because it makes them look good. I do volunteer work in the local prisons dealing with substance abuse and job skills and the subject tends to grab my attention.
That's good that you're doing that volunteer work, thanks for your service. The point that I've been making from the beginning was that, contrary to what his apologists say, this guy was NOT "infraction free" in prison. He was/is in drug rehab, which means, given the time that he was in prison, that he was doing drugs then. It's one thing for defenders of this cop killer to say that this guy turned his life around during his incarceration. But it's dishonest for them to say that his time was "infraction free," unless you consider that consuming illegal drugs is neither a crime, nor a violation of prison rules.