As the investigation into the death of Olivia Pratt-Korbel draws towards the end of its second week, it is clear extensive forensic work has been paying dividends.
Yesterday Merseyside Police revealed the gunman who killed the nine-year-old St Margaret Mary's Primary School pupil fired two different weapons during the shooting, on Kingsheath Avenue, Dovecot, on Monday, August 22.
Detective Chief Superintendent Mark Kameen, head of investigations, said he considers anyone willing to hide those guns in the "same category as the vile man responsible for this murder", adding "and we will hunt you too".
READ MORE: First picture of murder suspect as he appears in court
The revelation that a second weapon was fired at the scene is one example of how Merseyside Police is working with the National Ballistics Intelligence Service (NABIS) . NABIS was set up to support police forces across England and Wales in investigating firearms discharges and has a close working relationship with Merseyside Police, recently using the force's response to gun crime as an example of "best practice" in national guidance.
NABIS scientists are regularly asked to analyse microscopic markings on bullets that can show whether they were fired by the same gun, and this process will be ongoing as part of the investigation into the death of Olivia, 28-year-old Ashley Dale and 22-year-old Sam Rimmer - all shot dead in six horrific days across Liverpool.
Merseyside Police has not confirmed or denied whether NABIS has found evidence the guns fired in those incidents are "linked series" - i.e. linked to other shootings involving a weapon that has not been recovered.
If, however, there is a hit on a previous incident, that information could open up a whole series of new avenues for investigation around who controlled that weapon and any criminal allegiances they would be likely to hold.
The ECHO understands Olivia's death is believed to be linked to a dispute between established, family based criminal gangs - rather than younger post-code based street gangs as in the murder of 11-year-old Rhys Jones in 2007.
Although the work of expert forensic scientists can produce a remarkable amount of information from bullet casings and gunshot residue, locating of the murder weapon could be the ultimate key to solving the case.
DCS Kameen said yesterday: "I believe at this time that the gunman brought both of these weapons with him and that they were still with him when he callously ran away from Olivia’s house. I want to know where those guns are now.
"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.
"I would repeat the fact that the actions of the person who carried out this cold blooded attack do not command loyalty in any way, shape or form and Olivia’s family need to know that everyone responsible for her murder have been caught and convicted.
"So I ask you again – where are those guns now?"
Anyone with information is asked to DM @MerPolCC or call @CrimestoppersUK anonymously on 0800 555 111 quoting log 22000621096. You can also pass information on our Major Incident Public Portal website mipp.police.uk
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