Detectives investigating the Grenfell Tower fire have conducted three interviews under caution over potential offences relating to the disaster – including manslaughter.

“The police investigation into the Grenfell Tower fire has moved to a new phase with a planned programme of interviews under caution,” Scotland Yard said in a statement on Wednesday, adding that more interviews would take place in the coming weeks.

The interviews, carried out since late June, came as detectives investigated possible charges of gross negligence manslaughter, corporate manslaughter and breaches of the Health and Safety Act relating to the fire last summer that killed 72 people.

A spokeswoman for the Metropolitan police said the force would not confirm whether three separate suspects had been interviewed, or whether the same suspect had been interviewed more than once.

No one has been arrested for offences relating to the fire itself, though individuals who allegedly falsely claimed to have lived in the tower to receive compensation have been arrested on suspicion of fraud.

Yvette Williams from the campaign group Justice4Grenfell said she welcomed the development in the investigation.

But she added: “It’s unfortunate that it’s taken months after it happened, because if it had been somebody responsible like a member of the public, they would have been called in in June last year.

“But we do look forward to the police doing a thorough investigation and that they are already thinking ahead in terms of gross manslaughter charges can only be a positive thing.”

Officers have spent the last year scouring the tower for forensic evidence and plan to hand back control of the building to Kensington and Chelsea council in early August.

Commander Stuart Cundy said: “The handover of Grenfell Tower by the police will only occur once we are entirely confident that all police work has been completed at the tower and handing the tower over to the responsible body will have no bearing on the ongoing criminal investigation.

“The concerns of the bereaved, survivors and residents as well as the wider community will be central to how the handover takes place. We recognise this will be a significant milestone and one that is bound to stir a range of emotions for all those affected by this tragedy.”