Liam Whoriskey (25), from Glenabbey Gardens in the city denies manslaughter and one count of child cruelty against him following the death of the three-year-old in 2017.
The child was found dead in his bed in his family flat at Colmcille Court in the Bogside area on Sunday, September 17 around 10 am.
Kayden lived in the flat with his mother Erin McLaughlin and his five-month-old baby sister while Whoriskey was engaged to be married to Miss McLaughlin.
She had gone out socialising on Saturday, September 16, and left Whoriskey to babysit her children.
The Belfast Telegraph reports that after 15 days of evidence at Derry Crown Court from 27 prosecution witnesses and four defence witnesses, prosecution barrister Peter Irvine QC started his summing his summing up of the case to the jury of six men and five women.
Trial judge Philip Babington told the jurors on Tuesday morning that following legal discussions with the defence and prosecution, he was removing a charge of the defendant causing Kayden’ death by neglect from the bill of indictment.
He also told the jurors that one of the child cruelty charges which related to a fracture of Kayden’s fifth left rib would not require their consideration.
Last week Judge Babington amended the first charge on the bill of indictment from murder to manslaughter.
During the trial the jurors were told that the child, who was found with 15 blunt trauma injuries to his scalp, died as a result of the swelling of and bleeding of his brain.
Kayden’s mother Erin McLaughlin, who was questioned for two days by police officers investigating the death of her son, had stayed out overnight socialising with family members and friends on the day her son died.
In his closing speech to the jurors Mr Irvine said they had they had to consider all of the evidence without sympathy nor prejudice and they had to assess the evidence coldly and calmly.
He told the jurors to use their common sense and experience of life in coming to their decisions.
The prosecutor said there were several indisputable facts in the case.
He said the injuries to Kayden were non accidental and were not visible to anyone prior to the child going to bed.
Mr Irvine told the court that no-one else entered the family flat after Kayden’s mother had left him in the sole care of the defendant therefore, he submitted, the only inevitable conclusion was that the blunt trauma injuries inflicted on Kayden were caused by the actions of the defendant.He said: “How in heaven’s name did that young boy end up with 15 bruises to the scalp and others to the face and body that evening when he went to bed in a perfectly physical and sound condition, when he was in the custody and in the care of the defendant in this case?
“There is absolutely no suggestion anyone else other than the defendant was present in that flat from 7 pm in the evening.
“There is not a shred of evidence in this case that Kayden had any marks on his face or on his head and on any other part of his body prior to the defendant being left alone with him that evening.”
The jury will hear a closing speech from defence barrister Ciaran Mallon QC this afternoon, Tuesday, October 15.