McCullough pleaded guilty in Julypublished at 10:49 British Summer Time 11 October
McCullough is back at Chelmsford Crown Court where, in July, she admitted two counts of murder.
She appeared at that hearing via a video link from HMP Peterborough and replied "guilty" to both charges.
Police later revealed she had fatally poisoned her father with prescription medication. McCullough went on to stab her mother to death after beating her with a hammer.