The jury in the trial of Anxiang Du has been hearing how a schoolfriend of Alice Ding saw a man of Chinese origin acting, as she described "weirdly", outside her friend's house on the day of the killings.
The prosecution claims 54 year old Anxiang Du killed the family in a revenge attack after losing a long running legal battle.
Du denies murdering Jeff Ding, His wife Helen and their daughters Xing and Alice.
Click below to watch a report from ITV News Anglia's Emily Knight
A Judge has described how Anxiang Du was a "man on a mission" on the day he killed a Northamptonshire family.
Today the man who repeatedly stabbed a family of four was found guilty of murder in what was described in court as a cold-blooded massacre.
A killer who massacred a family of four was able to flee the country after police mishandled a 999 call from one of the victims.