Possible spoilers, mostly speculation and blatant Kiryuu fannishness. There is widespread (i.e, a thread in 2channel and a comment on the actor's blog) rumormongering about Kiryuu coming back. (Despite the writers having no idea of what to do with him.) But inevitably someone will protest that Kiryuu is a condemned criminal, if he comes back he should go straight to prison.
As I recall, he was serving a life sentence, but death usually terminates those, and he’s dead twice over. I don’t know exactly what the sentence was for. He has the reputation of a killer, but the most incriminating scene turned out to be an exaggeration.
I’ve seen arguments that an explosion he caused “was likely” to have killed someone, at least if the equivalent thing had happened in real life. I don’t think arguments from real life are very applicable to YGO 5D’s. Also, arguing from likelihood raises problems for:
Aki, who is likely to have done serious injury or death without even realizing it in her Black Rose Witch period. A murderer for a heroine seems fairly inappropriate for this type of show.
Carly, who may not have killed Divine after all, but not for lack of trying. Of course you could argue the Earthbound God made her do it, but she was the one with the grudge, not Aslla Piscu.
Jack, who certainly exposed Rally to reckless endangerment.
Yuusei, who drove Ghost off the road. That fall “was likely” to kill a human, and Yuusei didn’t know otherwise at the time. His “Saviour” dragon in general seems like more of a killer dragon to me.
Jack and Crow have also stolen cards (possibly the YGO world’s worst offense) and D-wheels, and Crow and Yuusei have also fought against Security. None of the whole list have atoned or even apologized to the victims, to my knowledge.
I think it’s safe to say that memories are really, really short in 5D’s.
ETA: To clarify, I'm not saying Kiryuu's innocent by any means. I'm saying he's paid the price for his crimes, whatever they were. So I don't see why he's the only one who gets named as needing to go to prison.