Aside from the fact that nothing we know of, excluding pure energy can escape from black holes.
They affect both space and time in a manner that nothing else can quite compare to, and usually have smaller black holes orbiting the supermassive black holes.
Aside from this, not much is known about these naturally occurring eaters of everything.
That said, additional information tells us that blackholes both have a North and South Pole, and also drift through space.
Also to be noted, they have strong electromagnetic fields near the horizon.
Now although unconfirmed, it's assumed that these magnetic fields are generated by an object orbiting the blackholes.
Now onto magnetic fields/waves.
Despite my hours upon hours of researching, I couldn't find any facts stating that electromagnetic fields/waves have any weight value.
Although I did find out that it is possible to transmit information using electromagnetic fields/waves.
That said, until proven wrong I can safely theorize that black holes do generate electromagnetic fields, possibly even generated after the horizon and escaping. (However, I am uncertain, just as anybody else is.)
That said, in theory, if you can figure out how to map objects with electromagnetic fields/waves, you could very well study the internal area of a black hole. Of course, the previous theory would also have to be correct.
Is it possible to investigate the inside of a black hole using electromagnetic waves generated after the horizon?