Kinniburgh was gunned down outside his home at Kew, in Melbourne’s inner east.
Stephen Asling was arrested in Geelong in November 2015 over the murder and is facing a committal hearing this week.
The court previously heard police believed underworld figure Terrence Blewitt was also involved in the shooting.
Detective Sergeant Sol Solomon from the Docklands Homicide Squad told the court about conversations he had with Carl Williams in Barwon Prison in December 2008 about the murders of Terrence and Christine Hodson in 2004.
Detective Solomon cited notes from the meetings, which were held between December 22 and December 29, 2008.
“Steven Asling and Terry Blewitt are the shooters. Blewitt is now dead. He [Williams] provided the firearm. He [Williams] procured the murder of Kinniburgh.
“He [Williams] would need an indemnity before he made a statement and gave evidence. He [Williams] has further knowledge, which he is willing to provide at a later time.”
Police found human remains believed to be Blewitt’s at Thomastown in January , but they were unable to be formally identified.
He had been missing for more than a decade.
‘Likely three different guns were involved’
Detective Solomon said an application was made to the Director of Public Prosecutions for an indemnity for Williams prior to his death, which he believed was going to be granted.
He said a statement was never obtained from Williams in relation to the murder because he was killed in Barwon Prison in April 2010.
Asling’s defence lawyer Matthew Goldberg said Detective Solomon “failed to convey that information to anyone in the police force after Williams died,” to which the detective replied: “That decision wasn’t made by me”.
Senior Constable Phil Stephens gave evidence about the bullets found at the Kew crime scene. He said it was likely three different guns were involved.
He said he found Kinniburgh at the scene with a pistol “resting on his right wrist”.”The pistol was cocked but the slide was not fully closed,” he said in a statement.
Detective Senior Constable Sally Webber, who has been investigating Kinniburgh’s death since 2013, was also pressed about which other persons of interest — including notorious gangland hit man Andrew Veniamin — were investigated following the murder.
She said the focus was on Mr Asling.
Detective Senior Constable Webber will continue giving evidence before Magistrate Jan Maclean when the committal resumes tomorrow.