I don't know. I'm not sure how easy it is to do something like that or how much power he would have had to do that.You don't think a multi-term senior senator planning to run for POTUS in the near future could do anything to scrub evidence or build an alibi proactively, in 1993 when basically all documentation was still paper?
All I know is that I believe she was raped until we have reporting that contradicts it. Because that's what accusers deserve. Biden doesn't need your protection, he's already got it from a plethora of others.
Also, again, in 1993 I don't think that incident would be thought of as "I need to protect myself now". His response, according to her story, was one of rejection and immediately tried to humiliate her for it, not "holy shit I need to prepare for retaliation".