Three people arrested yesterday on suspicion of conspiracy to assist an offender in connection with the Ding family murders have been released on police bail.
University lecturer Jifeng Ding, his wife Helen and their two daughters were found stabbed to death in their home in Northampton on May 1.
The 54-year-old woman who was arrested in Coventry, the 39-year-old woman arrested in Gloucester and the 25-year-old man from Islington in London were interviewed at police stations yesterday.
Police investigating the murder of a family of four killed in their home in Northamptonshire are renewing their appeal to find the killer.
A close friend of a family stabbed to death in their home has criticised detectives saying more should have been done to catch their killer.