EPQ help? Watch
Alternatively, if you're interested in the techniques used, try looking up methods such as bloodstain pattern analysis or DNA sequencing, and talk about how they are employed (this can take about half of your EPQ) before moving on to evaluating them compared to other methods, or just generally (e.g. how widespread, how valid etc.) Hope this helps!
Source: Psychology A2 student and should be on track for full marks on a biology-based EPQ