I don't want to sound like I don't believe in black holes... I do as a matter of fact.

However, I do not believe it is ever possible to theoretically observe an object "pass" the boundary of an event horizon. The most we could ever observe would be the object becoming infinitely close to the boundary.

I do believe the object would apparently disappear due to infinite gravitational time dilation. (Conservation of energy of light reflected from object)

I believe that the only mass observable in our reference frame is the mass involved in the initial collapse, thus forming the black hole.