A newborn baby girl who was discovered fatally injured at a house in Sheffield died as a result of stab wounds, police have said.

The baby was found at a house on Holywell Heights in the Wincobank area on Sunday morning, after police were called to reports of concern for her safety.

South Yorkshire Police said despite the best efforts of police and paramedics, the baby died at the scene.

Seven people aged between 15 and 37 were arrested on suspicion of her murder. Two of them, aged 26 and 37, were later bailed, but police confirmed on Tuesday a warrant had been obtained to extend time in custody for the remaining five as inquiries continued.

Det Ch Insp Tom Woodward, leading the investigation, said: “We recognise this is deeply distressing for those who would have loved to have a chance to love this baby girl, for the emergency services who responded and for the community who will inevitably be shocked by this incident.

“Everyone involved in responding to this tragedy – from the first officers and paramedics on the scene to the detectives now leading the investigation – has felt the profound impact of this investigation.”

He added: “Our commitment to this little girl is unwavering. We will confront every difficult and distressing challenge and pursue every line of inquiry with determination and care to secure justice for her.

“We know the local community will hold her in their thoughts and support us as we work through this complex investigation.”

A South Yorkshire Police spokesperson said officers were continuing their investigations in the Holywell Heights area and asked anyone with information that might be useful to contact them.