Don't have links, but that was reveealed in testimony. George admitted on the stand that the tape was his.
Other comments (paraphrased):
"This jury had an unreasonable expectation of forensics...their verdict was not based on looking at the evidence...it wasn't that couldn't look at the evidence, they didn't look at it...they were not being reasonable in what they can see and should see...there was no ability to determine the cause of death because of the decomposition, Casey should not have been rewarded for that and she was (rewarded)...I cannot believe they looked at the same case as the rest of us...this isn't the media's fault, it's the jury's fault."
Duh-uh. The tape was in the house in which Casey Anthony lives. The entire family had access to the tape. Do you think George - having killed Caylee with duct tape - would have run off to a “Find Casey” rally bringing with him the same, unusual duct tape?