Police in Western Australia are offering a $1 million reward to solve the murder of a mother and son whose deaths have baffled investigators for four months. Erica Coyne, 69, and her son Lloyd Mitchell, 50, were killed inside their home in the Spencer Park suburb of Albany, about 400 kilometres southeast of Perth, on February 8. On Tuesday, detectives released CCTV footage showing Coyne shopping at a local IGA and walking home along Mokare Road, as well as Mitchell riding his bike in a shopping centre car park — their last known public movements.