I raced across the Isle of Mull as fast as I could. I managed to intercept LR just as she was about to climb into a taxi, observed by O and R.

The car screeched to a halt, I leapt out, and ran over to my accomplice.

‘Put this on. Fast!’ I demanded, handing over a stocking mask.

I knew it was a huge risk for us to don our disguise in front of O and R. I prayed that they would turn a blind eye, and that the identity of the murderers of Mull would remain a mystery.