Murderer Anthony Hardy was released from a psychiatric hospital last year after doctors said he posed no risk to the public.
Anthony Hardy was released from hospital in 2002
The following month, he had killed two women. On Tuesday, he pleaded guilty to three counts of murder.
He had been sectioned under the Mental Health Act because he was considered a danger to himself and others.
He was a patient at St Luke's Psychiatric Hospital in Muswell Hill, north London.
It is understood he was freed by a mental health tribunal in autumn last year.
But in December the remains of Brigitte MacClennan, Elizabeth Valad were found at his flat and in dustbins.
Before their murders, Hardy had been a psychiatric patient after Sally White had been found dead at his council flat.
He was freed after it was decided she had died from natural causes and doctors did not consider him a danger.
The Camden and Islington Mental Health and Social Care Trust - which covers St Luke's - Camden Council, the North Central London Strategic Health Authority and the Barnet, Enfield and Haringey Mental Health NHS Trust said they would be commissioning a review of the case.
Their statement read: "Anthony Hardy has admitted he was responsible for three dreadful murders that took place in Camden.
"All the agencies involved join together to express their deepest condolences to the families of his victims and their sympathy to local people.
"Several agencies have already conducted internal management reviews of their involvement with Mr Hardy.
"In accordance with current guidance and normal NHS procedures, the Strategic Health Authority has decided to commission an independent review."
Mental health charity Sane said questions would be raised concerning the decision to release Hardy from psychiatric hospital.
Chief executive Marjorie Wallace said: "We cannot comment on the details of this case.
"However, it is known that Anthony Hardy was discharged from a psychiatric unit to receive care in the community because he was judged not to pose a risk.
"Once the court proceedings are completed, we will be questioning the judgments that led to that decision."