Two guns were used in the shooting which killed nine-year-old Olivia Pratt-Korbel in Liverpool, police have said.
Merseyside Police also released CCTV footage of the gunman running from the scene as they appealed once again for people with information to come forward.
Detective Chief Superintendent Mark Kameen warned those who are “shielding” the culprit that they “will do everything legitimately possible to bring you to justice”, adding: “It is beyond comprehension how anyone can protect a person who is responsible for killing a nine-year-old little girl.”
In an update on Thursday afternoon, Mr Kameen said the investigation had made “significant progress” and that it was believed the gunman had brought two weapons with him when he “callously ran away from Olivia’s house”.
“I want to know where those guns are now,” he said.
“You may have been told to hide them or dispose of them — I understand you may be frightened of contacting us, but I want you to do the right thing for Olivia and tell us where they are right now.
“If you are hiding the guns and you have no intention of telling us, then I place you in the same category as the vile man responsible for the murder. And we will hunt you too.”
Mr Kameen said the CCTV was being released in the hope that it might jog people’s memories about seeing the gunman in the area at the time of the incident on August 22nd.
“This footage shows the gunman running along Finch Lane away from Kingsheath Avenue. You then see him turn right into Berryford Road and go out of sight. We know he is climbing into and through people’s gardens to avoid being seen,” he added.
“As you can see, the gunman was wearing a black padded jacket and a black balaclava with a peak and black gloves, and he is described as approximately 5ft 7in tall with a slim build.
“This is the man we are hunting for — we need to know where he went that night or did you see him in the area?”
Olivia died after she was shot in her home in Dovecot when the gunman chased another man into the property.
Her mother Cheryl was also injured and is still receiving treatment for her injuries, police said.