can i rewrite the sentence as...

The suitable method to split the sentence :
War crimes fugitive Radovan Karadzic, whom has been arrested near Belgrade , posed as a doctor of alternative medicine, sporting long hair, a beard and glasses to hide his face.

War crimes fugitive Radovan Karadzic, which (cannot use which because he is a person) has been arrested near Belgrade, posed as a doctor of alternative medicine, sporting long hair, a beard and glasses to hide his face.

War crimes fugitive Radovan Karadzic has been arrested near Belgrade and (please change “and “ to “while” or “when” because the word “and” did not really tell the reader the timing between Karadzic was arrested and the time he posed as a doctor…)he posed as a doctor of alternative medicine, sporting long hair, a beard and glasses to hide his face.
Note : We used posed instead of posing because your sentences are in reported speech, while in the original sentence – the “posing as a doctor….” was additional information to describe the person.

War crimes fugitive Radovan Karadzic has been arrested near Belgrade. He posed as a doctor of alternative medicine and sported long hair, a beard and glasses to hide his face.