Marine Lourens05:00, Jun 05 2021 STUFF Listen: The 111 call Tristan Locke made after he fatally stabbed his neighbour Mark Cowling during a dispute over noise. “If I let go of him right now he's going to die,” Tristan Locke told a 111 operator after a dispute over loud music saw him attack his neighbour. MARINÉ LOURENS reports on the Father’s Day murder. An hour before Tristan Locke stabbed his neighbour to death, he called his grandmother. That’s what he usually did when he was feeling overwhelmed or distressed. It was only his mum and his grandmother who could comfort him when he felt this way. His relationship with them was very close, described by a psychiatrist as “unhealthy”.