Talk about it here.
In 2008, Dax Fex Fize Slitheen and Bloorm Vungah Bart Slitheen posed as Jay and Heidi Stafford. They went to the police and reported their son Ashley Stafford as missing. Robert Lines was responsible for the case. He did a missing report on TV together with the Slitheen. Chrissie Jackson recognised Luke on the TV and called the police. Robert Lines came to 13 Bannerman Road and sent Luke to Jay and Heidi Stafford. Then he arrested Sarah Jane Smith and drove with her to the police station. (TV: The Lost Boy)
However, Sarah Jane had powerful friends from UNIT so he had to release her. Even though Lines investigated Sarah Jane Smith and Luke's life with her, he did not think about investigating the past of the Stafford family. (PROSE: The Lost Boy)