I believe that there appears to be some confusion between blood evidence and DNA
Sea water would do a comprehensive job of removing DNA evidence....hence why bodies of water are such popular deposition sites for murderers.
Traces of blood could still exist on washed skin (proteins and enzymes) after washing but these too degrade over time.
Obviously a strangulation or asphyxiation would leave little or no blood evidence but MAY leave some contact DNA but this is not certain to happen
Also exposure to the elements would degrade the overall quality of evidence versus a body found indoors.
The focus on the discarded top i feel may be overanalyzing it.....i think that he would be well aware of the presence of cctv...thus in the naive and arrogant mind of his.....he thinks that wearing a top and then removing it would be sufficient to fool a viewer of the recording.
I also attribute the scattering around of evidence as another naive attempt to mislead..in his mind nobody would link items dumped in different places together
I feel that the evidence quite strongly points to a total lack of planning and a complete lack of criminal know how.
As with anything in life, despite being pretty inept he has had a measure of fortune....i believe that the lack of DNA at the mcphail property cannot really be viewed in any context without knowing exactly how the victim was removed from that property.
Who knows that he didnt manage to persuade her to walk out of the flat without any sort of struggle?
Who knows that she was not standing in the doorway as he approached?
All in all and taking what i have seen thus far
I feel that there is enough here to require a pretty spectacular defence performance in order to rescue him here.
I do not believe that this was calculating planned and carried out....much more an opportunist crime and with more efficient and conciencious policework this trial would have been an absolute formality.
But lets be fair here....when news of this crime first broke...who thought that we may be looking for a young boy as the offender?
I just hope that this case is resolved in a way that offers a crumb of justice for the helpless victim.