A 23-month-old toddler found dead in an empty house died of multiple multiple stab wounds, police were called to following reports of a domestic incident.
Police Officers arrived at the home in Wythenshawe, Manchester, just after midnight on Sunday evening and a man and woman had left the semi-detached home to go to hospital.
A 30-year-old woman was arrested on suspicion of murder and remains in hospital for treatment.
Formal identification has taken place and the boy’s family are currently being supported by officers.
A post-mortem examination concluded that the boy died from multiple stab wounds.
Detective Inspector Carl Jones of the M.I.T said: “This is a truly distressing investigation and we are doing everything we can to find out exactly what has happened.
“The family wish for their privacy to be respected at this time and I’d ask that people do not speculate around the boy’s identity to allow them to grieve and come to terms with this tragedy.
“We have one person under arrest but need those who have not yet passed on information to come forward.”
A 31-year-old man who was also arrested in connection with the murder has subsequently been released without charge.