Extracting DNA from the air – DNA evidence of human occupancy in indoor premises

From the abstract:

> Detectable levels of DNA were also observed in air and dust samples from ultra-clean forensic laboratories which can potentially contaminate casework samples.

Great news for criminal defense attorneys.

It cuts both ways, there was this high profile case of the son of a very rich and powerful family brutally murdering his working class girlfriend in his family mansion with some family present, motives still unknown.

In the autopsy they discovered sperm from a 3rd person on her body, tried to claim that it was an infidelity case(you get different sentece depending on your motives and circumstances) but later it was revealed that this was just a contamination during the autopsy.

So, the more forensic options the better but likely longer and more expensive trials. All lawyers win.

> just a contamination during the autopsy.

How does sperm end up on her body during the autopsy? Are we talking necrophilia or are there multiple murdered bodies laying next to each other and the tools are re-used or something?