Jifeng Ding and Alice Ding died from stab wounds, police have revealed A suspect in the investigation into the murders of a couple and their two daughters has been named by detectives.Police said Anxiang Du, 52, was being sought in connection with the deaths of the family who were found stabbed in their home in Pioneer Close, Wootton, Northampton, on Sunday night.
The family was named locally as college lecturer Jifeng Ding, his wife Helen Chui, and daughters Alice and Xing.
Police said Mr Du, from Coventry, had left a suicide note.
Mr Du left a note to his family implying it was time to say goodbye.
He is understood to have been a business associate of Ms Chui dealing in herbal remedies.
The 52-year-old left his home in Coventry at 1030 BST on Friday to go to work in Birmingham but never returned.
He was last seen on 29 April in Birmingham City Centre, Pallisades Shopping Centre and was wearing a white baseball cap, brown waist-length coat, grey trousers, a blue woollen top and black leather shoes.
He was described by police as being of slim build with a bald patch.
Police said they were still looking for a murder weapon.
The bodies were found in a house in Pioneer Close, Northampton Det Supt Glyn Timmins said: "The public should be cautious. The reason being is that, obviously having left a suicide note Mr Du had a particular state of mind.
"What I can say is that he's likely to be frightened, he's likely to be quite desperate and certainly when, and if, he sees this in the media he's certainly going to be very anxious and nervous.
"Therefore I think the prudent thing to do would be to assume that Mr Du should not be approached and that's a job for the police if and when he's sighted."
Earlier, police said they did not think the family were victims of a random attack.
They are believed to be investigating the background of the family - who are of Chinese descent - to try to establish a motive for the murder.
Police also want to trace a silver five-door Vauxhall Corsa, registration BG60 PMO, that was hired by one of the family members and was last seen on Friday.
'Shocked and saddened'A tribute page set up on Facebook to Nancy, 18, who has the Chinese name of Xing, and Alice, 12, has been joined by more than 1,500 people.
On a separate page, comments have been made by students at Manchester Metropolitan University in praise of Xing and Alice's father Jifeng, who was known as Jeff.
Helen Chui is believed to have worked locally as a teacher.
Manchester Metropolitan University said it was "shocked and saddened by the news of the death of Dr Jeff Ding".
"As a senior lecturer, Jeff was a popular and dedicated member of staff who joined the university in 2004," a university spokesman said.
"Jeff will be very sadly missed by all his colleagues in the division of chemistry and environmental sciences, all our staff, students and his friends at Manchester Metropolitan University and by the wider academic and research communities."
Babatunde Adekoya, from the student union at the university said: "You wouldn't find anyone as delightful as him throughout the university. He was always ready to help students in their time of need."
Det Supt Glyn Timmins said police want to question 52-year-old Anxiang Du
