The real question here is what mystery? Patsy Ramsey died six years after this film was released, so it is no longer undiplomatic or libellous to name her as the killer. Detective Steve Thomas has, undoubtedly, described in minute detail what almost certainly happened.
The Ramsey case is striking similar to the very slightly later murder of Billie-Jo Jenkins. Her foster father Siôn Jenkins (no relation) was convicted of her murder, lost an appeal, won a second appeal, then stood trial twice more, both times the juries being unable to reach verdicts. As a result, the judge at the third trial directed the jury to find him not guilty. Jenkins is believed to be the only man to be tried three times for the same murder in England and to have walked away without a proper finding of not guilty.
As with the Ramsey case, the defence tried to muddy the waters, here by claiming there was another suspect, a mentally deranged man, who had been seen in the area. In the Ramsey case, the emphasis was on paedophiles or someone who had a grudge against John Ramsey. The reality though is that Jenkins and his two young daughters were the only other people proven to have been at the crime scene at the material time. When the girls are ruled out on account of their age, who does that leave?
Similarly, there were only four people in the Ramsey house at the time. Burke can be ruled out; he would never have been able to bear up under questioning. That leaves only John and Patsy, and as John didn't write that absurd note, who does that leave? The only real questions are at what point did John cotton on, and did he ever confront Patsy? The answer to the first question must surely be as soon as he saw the note. He wouldn't have had even to read it to realise who wrote it.
There is one major error in this film; Patsy is shown putting on her make-up prior to "discovering" the note. We know she was up all night because she answered the door to the police in the clothes she had been wearing the previous night, and streaked make-up. Mystery solved.
