The Met Police Commissioner said she is “dumbfounded” by allegations that two of her officers shared “inappropriate” photographs of a double murder scene.
The bodies of sisters Bibaa Henry and Nicole Smallman were found earlier this month at Fryent Gardens in Wembley.
The officers have been arrested on suspicion of misconduct in a public office and suspended from duty.
Dame Cressida Dick said she was appalled and disgusted non-official photos had been taken and shared.
The Independent Office for Police Conduct (IOPC) said the pictures were allegedly “shared with a small number of others”, adding that the Met was “handling matters involving those members of the public who may have received those images”.
Dame Cressida said: “I don’t know all the details but if it is as it appears to be then it is shocking.
“It is disgusting and the whole of the Met would condemn what has happened here.
“If those officers’ actions have added to the families’ unimaginable distress, then I apologise from the bottom of my heart.”
The sisters’ family previously told of the “devastating impact” of their loss after their loved ones’ bodies were found next to each other shortly after 13:00 BST on 7 June.
The IOPC is separately investigating how the Met handled calls from worried family and friends of the sisters after they went missing.
Asked if she accepted criticism that there may have been an element of institutional racism in the police response to the double murder, Dame Cressida said: “This is a horrible, horrible double murder of two beautiful young women.
“My heart goes out to their family. It is just appalling.
“We have an enormous investigation, very well resourced and using all the expertise not just in London but all across the country and beyond.”
Police previously released pictures of senior social worker Ms Henry, from Brent in north-west London, and photographer Ms Smallman dancing with fairy lights before they were murdered.
Their last contact with friends and family was about 01:05, police said.