In his closing speech, he said: “He put a stop to Darcy screaming. He did that by shaking his five-week-old daughter violently.
“As a result, his five-week-old daughter sustained a catastrophic head injury and she would have stopped breathing almost as soon as she received that fatal head injury.”
Sandhu told the jury Clark had been living at a “tidy and well-presented” home and gave the impression of being a mother who was in control while hiding the fact she “drank a lot of alcohol and she took cocaine”.
He said: “The impression Amy Clark gave hid the truth.
“Beneath the veneer of the well-presented and ordered life she wanted others to believe she led, was a more chaotic existence which flowed, no doubt, from her alcohol and drug use.”
Both parents were taking drugs during their daughter’s short life, the trial was told.
Jefferson and Clark opted not to give evidence in their defence during the trial.
Sandu said: “They have remained silent because they each bear some responsibility for the events that led to their daughter suffering injuries and their daughter being killed.