Relatives of a family-of-four murdered in their home have described the "terrible" impact of the deaths.
Jifeng "Jeff" Ding, his wife Helen and their daughters Alice, 12, and 18-year-old Xing were found stabbed to death in Wootton, Northampton, on 1 May.
Police are still hunting prime suspect Anxiang Du, 52, from Coventry, in connection with the murders.
Mr Ding's brother Jixiang said he was confident the family's killer would be caught and brought to justice.
He revealed the trauma being suffered by his parents in China.
"They are almost afraid of picking up a phone call," he said.
"You call them, you try to say something nice to make them feel better, but that itself reminds them of my brother and sister-in-law and their grandchildren.
"That just reopens a wound and that is just terrible. I still don't know how to help them in that regard and that is the most difficult part."
Mr Ding, a biology professor from Kentucky in the US, also told of his own difficulty in coming to terms with the killings.
"I actually found out from the internet. I was completely shocked. I could not finish the news story once I saw the pictures," he said.
"I could not believe that four people were gone. I mean, it is just complete shock and I cannot accept in a way that it is reality."
He said he had confidence in the police and believed the person responsible would be punished "sooner or later".
Mr Du, who worked at a herbal medicine shop in Birmingham, was a previous business associate of the dead couple but their relationship had soured and was the subject of a court case which reached a climax the week of the murders, police said.
It is thought he may have travelled to London in a Vauxhall Corsa that went missing from the family's home and was later found in a side street in St John's Wood in the capital.
Police believe Mr Ding, a lecturer at Manchester Metropolitan University, and his family were killed on 29 April.
Jixiang Ding said he had "many questions" to ask Mr Du about what happened on 29 April, when the killings took place.
"For a long time, even now, emotionally I don't want to hear his name," he said.
"But if he really did this - so far he is just a suspect - but if he really did this I have many, many, many questions to ask him.
"I want to ask him how could you stab a knife into an innocent girl's heart, not once but twice?
"I also want to know what he is feeling or whether he has any feelings when he saw the girls' expressions."
Mrs Ding's sister-in-law Li Zhu, who lives in China, appealed for help in finding the person responsible for the deaths.
"We hope that friends, the Chinese community or the public in the UK, China or around the world will do everything they can to assist the police to find the murderer," she said.
Crimestoppers has offered a reward of £10,000 for information which leads to the arrest and conviction of the killer.
Mr Du is described as 5ft 9in, slim and with thinning hair and he regularly wears a baseball cap.