Sure, but we all know how far we trust the DOJ.* I would at least like to see Congress look into it. Not that Congress has a great track record lately, but at least they are a different branch of government, rather than being the same department, under the same corrupt leadership.
*To be fair, they had the decency to admit there was no identifiable racism or wrong-doing in the Michael Brown or Trayvon Martin shootings.
Honestly I'd rather have DOJ look into it. As you pointed out they have investigated, seemingly fairly,a couple of high profile cases that the boss would LOVE to have found racism in. They have the ability to actually bring criminal charges.
The last couple things that Congress has "investigated" (Bengahzi, this issue last time, TARP funds usage, G-bay, the whole Bergdahl thing, Fast and Furious) has led me to strengthen my belief that a congressional investigation is where an issue goes to be swept under the rug.
Not saying that the DOJ is a paragon of trustworthyness, but they
might do something. Congress won't.