Essex Police say they will refer themselves to the Independent Office for Police Conduct to review their response to the deaths of three men in Colchester.
Police were called to Wellesley Road at around 10.15pm on Saturday 5 October following reports of an altercation.
Danny Gibson, 35, and his brother 31-year-old Jason Gibson were found dead in a house on Wellesley Road.
Richard Booth, 35, also from Colchester, was found dead inside a car in Hospital Road. Post-mortem examinations concluded that the men died of multiple stab wounds.
Tom Saunders, of Bounstead Road, Colchester, is charged with three counts of murder on October 5.
He is also charged with possession of an offensive weapon in a public place.
Saunders spat towards the public gallery from behind the reinforced glass of the dock as he appeared at Colchester Magistrates' Court yesterday. He will appear at Chelmsford Crown Court later today.
Colchester district commander, Chief Inspector Rob Huddleston, said the incident is being treated as "targeted and isolated".
"Those involved were well known to each other and we do not believe it was linked to any gang-related crime or drug use," he said.