Young child's body found at home after mother-and-son deaths in Dartmoor

British police have launched a murder investigation following the deaths of a mother and her son at Dartmoor and the discovery of a second child's body at the family's home.

The 24-year-old woman, named in reports as Katharine Hooper, and her five-year-old son died after falling from rocks at Haytor in Devon - one of Dartmoor's most famous landmarks which is popular with walkers and climbers.