Police investigating the murder of a family of four have increased a reward for information leading to the prime suspect's arrest to £25,000.
Detectives hunting Chinese businessman Anxiang Du, 52, raised the reward from £10,000 almost 12 months since university lecturer Jifeng Ding, his wife Helen Chui and their two daughters Alice, 12, and Xing, 18, were found stabbed to death at their home in Wootton, Northampton, on May 1 last year.
Detective Chief Inspector Tom Davies said a national manhunt was continuing, but the search for Du - who has not been seen since the day of the murders - had spread internationally with the help of Interpol and the Serious Organised Crime Agency (Soca).