Re: Justice.
I dont agree they should both be charged, that is wrong if one is not guilty. A person is innocent till proven guilty in this country and that should go for any murder.
It is up to the police to produce the evidence, it may take months to break the murderer down, but they have to.
The forensics might be wrong anything can be a problem, they may have alibis that the police can't refute, maybe witnesses are mistaken about time etc.