Maddie Durdant-Hollamby, 22, was stabbed to death and her boyfriend died as a result of self-inflicted knife wounds, police have said.
Maddie's body was found by police at a property in Slate Drive, in Kettering on Friday (27 August) afternoon.
Northants Police had been called to the scene following a report of concern for her welfare.
The body of Benjamin Green, 41, was also found at the same property, which he owned, and it was previously confirmed that the two had been in a relationship.
Northamptonshire Police said preliminary post-mortem reports showed Maddie, who is from Wimblington in Cambridgeshire, died of stab wounds, and Benjamin Green of self-inflicted knife wounds.
The force said Ms Durdant-Hollamby’s death was being treated as murder and no-one else was being sought in connection with the incident.
It added that both families have been informed of the findings and continue to be supported by specialist officers.