After thanking the Lord for his assistance in murdering the father and son, Lynch dragged their bodies into the bush and buried them in a shallow bush grave, hitched their team of horses to the dray and headed toward the Mulligan farm to settle an old score.
As he rode up to the farmhouse, he saw Mrs. Mulligan sitting in a rocking chair on the porch. She asked where he had gotten the horses and dray and he replied that they belonged to a man in Sydney. Lynch inquired about the whereabouts of her husband, son and daughter, and Mrs. Mulligan told him that they were in the fields working.
"What do you want?" the woman asked.
"The £30 your husband owes me," he replied.
"What £30?" she asked.
"You know very well what — for the articles which I got from burglaries and highway robberies I did at the risk of my life and which your old man was supposed to be holding for me," Lynch said.
"There's only £9 in the house," Mrs Mulligan replied, giving Lynch the impression that she was fobbing him off until she could talk to her husband.
In his confession Lynch said, "I was much discouraged by her putting me off but I didn't show it. Being a fair man I decided to wait until her husband returned and give him the chance to pay me my money and if he refused then I would see to it that he would get to meet the Almighty."
Lynch then elected to walk to the Black Horse Hotel at Berrima and buy some rum in the belief that it would get Mulligan in the right frame of mind to pay him the money. On his return he saw Mr. and Mrs. Mulligan together on the verandah and they greeted him in a friendly manner.
Mrs. Mulligan fetched glasses for the rum, and they sat on the verandah drinking and chatting. Lynch eventually brought up the matter of the £30, and Mr. Mulligan asked him to be reasonable about the amount. Lynch left the verandah and sat brooding on a log nearby, deep in consultation with the Lord about what he was going to do next. The Lord gave Lynch his blessing to murder them.
After Mr. Mulligan had returned to the fields and Mrs. Mulligan had disappeared into the house, Lynch lured their young son Johnny into the woods on the pretext of cutting some wood for his mother.
Once out of sight, Lynch killed the boy with a single blow from his axe to the back of his skull, covered his body with brush and returned to the farmhouse.
"Where's Johnny?" Mrs. Mulligan inquired.
"Gone to the paddock with the horses," Lynch said.
Lynch thought Mrs. Mulligan suspected that he had murdered her son because she became hysterical and told Lynch to fire his gun to attract attention.
"What's all the urgency?" he asked. "He's all right. I only saw him a few minutes ago."
But the woman insisted that Lynch shoot his gun indicating to anyone within ear shot that all was not well.
"But if I do it will alert the police," Lynch said as Mr. Mulligan appeared and asked what was going on. Both the Mulligans were suspicious now. In fright Mrs. Mulligan returned to the house while her husband headed to the woods in search of his missing son.
He didn't get far. Lynch ran up behind him and, with one swing of the axe, felled him. After dragging the body into the woods, Lynch saw Mrs. Mulligan coming toward him. He tripped her up and killed her with one blow to the head from the axe.