As mentioned by @Hypnosifl, from the outside observers perspective things never do fall into the black hole. I wrote a whole blog entry about what that might look like and I wrote it specifically because of what appears in the movie Interstellar.
I wrote another post describing what Cooper might have seen as he fell into the blackhole.
From this and the fact that as far as our knowledge of the physical universe extends nothing escapes from a black hole; we can deduce that Cooper's interaction with the alien tesseract must have occurred above the event horizon.