One night, a woman was on her way home from a nightclub. She was quite near her house when a man grabbed her from behind, dragged her into a nearby park and raped her. Her cries were heard by neighbours living in nearby flats, enough so that one of the residents looked out of her window and upon seeing "some sort of attack", shouted "What's going on down there? I'm calling the police." At this point, the rapist fled.
About 10 minutes later, the police had arrived and the woman was being comforted. At this point, a man, who had just gotten out of a taxi, walked past and was stopped by the police and asked where he'd been.
The man told the police to piss off and was arrested.
The next day he was charged with the rape of the girl as the girl's description of her attacker was similar to the appearance of the man.
The victim, who was admittedly drunk beyond belief when she was attacked, could not positively identify the arrested man but the police held him anyway as "it was probably him".
The Procurator Fiscal (the CPS and DPP version in Scotland) took various items for forensic examination and these included a jacket worn by the victim when she was attacked. Upon initial examination there were found to be semen stains on the jacket. The DNA of the accused was taken and compared with the DNA of the semen.
The result came back negative with a note specifying that the chances of the accused being the person who had deposited the semen on her jacket was roughly 70,000,000/1 (70 million to one).
The accused was convicted of rape and sentenced to nine years in prison.
Why?
Because the Procurator Fiscal decided that they would proceed with the case, even without any forensic evidence AND in the face of conflicting forensic evidence strong enough to raise serious doubt as to the man's guilt.
When the victim was asked if she could explain semen stains on her jacket, she replied ,"I bought the jacket at a car boot sale and hadn't washed it since I bought it."
The man is currently awaiting news of an appeal against conviction.
So, to answer your question, I think the Procurator Fiscal would have gone after Michael Jackson even if he had produced evidence that he had been living in Japan for the past 25 years.