Sleuthster
Verified - friend of Wendy Huggy
They might be taking away part of the wall to test it with blood specific reagants.
That's what I think. From the story;
Investigators used chainsaws to dig out the portion of the wall with the stain, which will be sent to the FBI laboratory in Quantico, Virginia for analysis to determine whether the substance is blood and, if so, whose it is, the law enforcement source said.
So it could be part of the wall if there's no mention that they took this out of the basement prior.