Australia's Justice Minister, Chris Ellision, says Canberra will help in the trial of a Solomon Islands man charged in connection with the killing of a Ramsi solider.
Adam Dunning, a 26-year-old Australian Protective Services officer, died after being shot twice in the back during a patrol in Honiara last week.
A man who handed himself into police on Christmas Eve, 31 year old, John Hen Ome, has been charged with one count of murder.
He's also been charged with attempted murder in relation to another officer who was in the vehicle with Officer Dunning.
Senator Ellison said the 100 extra peacekeepers sent to the Solomons after the shooting may have pressured Ome to turn himself in.
Police in Solomon Islands are now linking the shooting with another firearms incident in October in which a regional assistance police officer was wounded.
In that attack, a Nauru police officer with the Regional Assistance Mission to Solomon Islands received minor shrapnel wounds after he and his Tongan colleague were shot at while on vehicle patrol in Honiara.
A Solomon Islander, James Tatau, is now wanted for questioning in relation to both incidents.
Ome is due to appear in court again on January 4.