They didn't botch anything.  They deliberately destroyed/contaminated the evidence against a fellow cop to get it tossed out.  Common practice--union endorsed.  A gang with a flag.

      What did they expect? this has been a "typical" cop-culture cover-up, since the moment it took place. It's almost certain that the "cops" are thinking that, if they can string this out long enough, confuse the facts long enough, abuse the chain of evidence long enough, and discredit the collective memories of the witnesses long enough, they'll be able to get this creep off. (From the beginning, when the blood test was purposefully tainted and discredited, by having it handled by an "unapproved" laboratory, this has been typical "cover our asses" sideshow. What's most distressing is that the victims remain the victims, dead and otherwise, and the "criminal" is aline and free...Such is life in the shadow of the new gestapo movement.)