When David Cass arrived to collect his daughters, Ellie, three, and Isobelle, just 14 months old, it seemed like a normal custody visit. Kerrie Hughes kissed them goodbye, never imagining it would be the last time she saw them alive.

The following day, he called Kerrie, out of breath, and said: “They’re sleeping.” When she asked what he meant, he replied: “They’re sleeping forever.” Moments later, he hung up.

Locked in a bitter split and custody fight, David had made a devastating choice — to ensure his daughters would never return to their mother.