this hasnt been brought up but there could be political motifs for killing Lennon. he had many problems with the US government, had been turned back at the boarder before, and had countless false accusations against him. while the killer none the less did something wrong, he could have sided with the government and did something that the government would not do as it would upset the public. Many government officials had a strong dislike of Lennon, and the ideas that he gave the public (anti-war, freedoms, ect.) and now the government is holding the killer in prison for doing something that helped them for an unjust period of time. Due to Lennon's ideas on peace, i think that he would have wanted the killer to be released, after serving a reasonable sentence.
Does not change the fact that we lost possible the greatest musician public figure ever that day. RIP John Lennon and vibes to Paul Lennon (His son. i think his name is paul)