to put together because you have to link the act that is a crime with the perpetrator and that is pretty tough for crimes against humanity and war crimes. the crime of aggression is pretty straightforward. the second thing that would happen is you d create that list of persons of interest and that, ithink, would begin to galvanise people s attention. more now on that ongoing street battles, in the ukrainian port city of mariupol. the mayor has told the bbc the fighting is stopping rescuers from reaching hundreds of survivors trapped beneath a shelled theatre. earlier my colleague matthew amriliwola spoke to anton levsiushkin, whose family has managed to escape from mariupol. he hadn t been able to reach his twin sisterfor 11 days. he s based here in the uk and begins here by explaining what his sister had said, about survivng in mariupol. they ve been for like two or three weeks now with no electricity, water, heating, nothing.