Rachel Fee, or Trelfa, admitted it was “a possibility” two-year-old Liam Fee might die and that if she had taken him to hospital for treatment for a broken leg, he would be alive today.
The High Court in Livingston heard that, despite suspecting her son had a broken leg for several days, she went to look after her horse for three hours on the day the boy died, 22 March, 2014.
Fee, 31, is on trial alongside her civil partner, 28-year-old Nyomi Fee.
The pair deny murdering Liam at a house near Glenrothes in Fife by repeatedly inflicting “blunt force trauma” to his head and body, and say another boy is to blame for the toddler’s death.
Questioned by prosecutor Alex Prentice QC, she said: “I know I should have got Liam help. It’s a decision I’ll regret for the rest of my life.”
Fee said she took responsibility for the decision not to get help as she was concerned the child would be taken into care, and she agreed under questioning that she had threatened to leave Nyomi Fee if she made the call.
She said: “I wasn’t thinking straight at all. I should have got help, I failed to do so. It was the wrong decision to make. I was frightened that they wouldn’t believe me.”
Fee said: “I completely failed Liam.”
The mother denied returning from the stables on the day of her son’s death and “striking him so hard you ruptured his heart”.
She also denied allegations of abusing two other boys, one of whom the couple are accused of falsely blaming for Liam’s death.
Fee became emotional when telling the court about the night Liam died.
She said Nyomi screamed for her to come to his bedroom where she was trying to get him out of his buggy, and she fell to the floor.
Fee said she asked the other boy what he had done and he said “I did this”, putting his hands to his mouth and throat.
She told the court: “I said ‘You’ve strangled him or suffocated him haven’t you?’ and he said ‘Yes’.”
She claimed the boy had shown sexualised behaviour for years and in the months before Liam died had began assaulting him sexually and physically, as well as another boy.
In a statement she gave to police four days after Liam’s death, read to the court, she said: “There are lots of other incidents involving Liam and (the boy) from the past but we would be here all day if I was to go into details.
“At a later time both myself and Nyomi would like to tell you about previous injuries caused to Liam by (the boy).”
Mr Prentice asked the witness: “Do you not owe it to the memory of Liam and his dad, who is sitting in court, to tell the truth about Liam?”
She said: “Definitely. I am telling the truth.”
The case was adjourned until Tuesday when the Crown and defence will begin summing up before the jury are given directions by judge Lord Burns.