Porter appears to have been dismissed by the authorities at the time as an old man incapable of participating in the killings, or making any contribution towards them.
But within Aboriginal society, he would have been a respected 'elder', and a very important person in Jimmy's eyes.
It is possible his role in what happened has been overlooked.
In July 1841, the wealthy squatter, Edwin Rouse of Guntewang pastoral run near Mudgee, was asked by the authorities about his experience with employing Aboriginals.
He stipulated that any prospective Aboriginal employee had to be beyond the control or authority of the Elders and Chiefs of the district.
Otherwise, whatever kindness was shown towards them, or however attached they became to a family, the connection would never be sustained so long as they came under the influence of their native rulers. [Source: Rouse Hill and the Rouses (1998), Caroline Rouse Thornton, p.290]
The attack on the Mawbey family as a whole, not just the individuals perceived by Jimmy as the main offenders, was traditional tribal behaviour under customary law.
'Payback' was meted out by the members of one family on the members of another, not individual on individual.
This was particularly so if the individual who had done the injustice had fled or been put in gaol.
If payback was prevented, justice was not done, so the family feud continued to fester.
It is for this reason that some Aboriginal legal circles are arguing today that the customary law of payback be respected by Australian lawmakers, and that the perpetrators of payback not be charged with a criminal offence or gaoled.
In their eyes, the traditional form of justice restores the natural order and the matter can be dropped, while intervention by our legal system just perpetuates it.
So it would seem that from an Aboriginal perspective, Jimmy was quite justified in killing innocent children because it was part and parcel of family payback.