If your hypothesis that 佢想要一個器官比佢老母用 is true, then there must be a 第3者作案. Since the killer didn't leave HK after the murder, someone else must have used the missing 行李喼 to carry the organ (with lots of dry ice?) back to 大6 for the transplantation. Most likely, this 第3者 is a close relative of the mother, possibly named 阿凱 (or similar?) who lives in 大6. Like you said, 純粹猜測.
@@truchoo Beggars can't be choosers. When you have no connection to power nor $$ to buy a young 器官 , you'll take whatever is available to you, no matter how old. It's a crime of opportunity.
I cannot tell if this killing is premediated or not, but I don't have doubt that the Police got the right person. The evidence showing him carrying bags out of the building multiple times in the middle of that same night and returning without them was damning.