Later that evening, she made a second call to 999, this time admitting she had stabbed Alan Williamson at her flat on Glenure Loan in Corstorphine, Edinburgh.

When police arrived at Melissa's flat, they found her hands covered in blood and 47-year-old Alan Williamson lying dead behind the front door.

Melissa confessed to the officers, saying:

"The power it gave me was amazing. I have severe mental health issues. I need to go to Carstairs (psychiatric hospital). We've been friends for ages, but this has been coming for ages."

In the kitchen, police discovered a six-inch knife, the weapon used in the attack.

Alan Williamson had suffered 29 injuries, including 12 stab wounds to the left side of his chest, 12 to his left upper limb, and five to his left lower limb.

Why had Melissa Young brutally murdered her neighbour? Had he really been troubling her and refusing to leave her flat? Or did Melissa Young have her own twisted motive?