Then you clearly haven't done any research. It's a big part of his and George Knapp's entire story.
Bob claims to have taken some from the lab did some test that showed it bent light and George Knapp filmed it for proof but, then lost the tape.
In the latest documentary with Corbell, it's one of the biggest portions of it. They go out in the woods and hide their phones to talk about the E115 he stole and they tried to claim the FBI raid happened after they talked about it. Corbell even claims to have found the tape George Knapp filmed of the E115 but, it was accidentally taped over.
Him claiming to have taken E115 from S4 was a big portion of the original story.