A Briton, Neil Crampton, has been charged with the murder of his two children, Abigail and Steven Crampton, his ex-partner, Mrs. Olufunke Sobo and her brother, Yemi Sobo in Newcastle.
They were found dead on Tuesday in Hawthorn Gardens.
The Briton, 34, is due to appear in court today.
Northumbria Police said post-mortem examinations revealed the four had suffered multiple stab wounds.
Detective Superintendent, Steve Wade, said a number of knives had been recovered from the murder scene.
He added: “Forensic scientists and crime officers will continue to work at the murder scene for several days in an attempt to gather further forensic evidence.
“I can confirm that the man arrested on Tuesday is Neil Groves Crampton, 34, who is the natural father of Abigail and Steven and the former partner of Funke Sobo”.
It would be recalled that the Nigerian woman, her two children and brother were found stabbed to death in their home in Gosforth, near Newcastle upon Tyne, United Kingdom.
Detectives immediately begun a probe into the murder with the questioning of Neil Crampton.
The UK police said all four were victims of knife attacks in separate rooms of the �350,000 semi-detached house in a tree-lined suburban street.
Officers said they received a call from a man saying he had killed his “entire family” in Newcastle.
They later found the bodies of Olufunke Sobo, 36, her brother Yemi, and her children, Abigail 12, and Steven Crampton, five, in Hawthorn Gardens.
Neil Crampton was arrested on Tuesday and taken into custody yesterday. He had not been medically fit enough to be interviewed.
Post-mortem examinations were also taking place yesterday afternoon, and expected to continue until today, to determine how the four died.