Baby Lucas Irvine 'clearly shaken' prior to death
A four-month-old baby boy died as a result of "deliberate and violent shaking", a court has been told.
Lucas Irvine died in hospital on 21 November 2010, four days after an incident at his home in Lancaster.
Christopher Roberts, 19, of Garth Lane, Knighton in Powys and Karen Irvine, 19, of Gerrard Street in Lancaster stand accused of his murder at Preston Crown Court.
They deny murder, manslaughter and allowing the death of a child.
Anthony Watson, opening the case for the prosecution, said Lucas had been "assaulted" and both defendants had been responsible.
"This was a deliberate shaking that caused severe injuries and Lucas died from those injuries," he said.
A post-mortem examination at the time of Lucas' death showed he had died from "non-accidental head and spinal injury" and that his brain was "massively swollen", which was consistent with "deliberate and violent shaking".
Mr Watson said there was "no doubt" that either Mr Roberts or Ms Irvine, who had a "volatile" relationship, had "clearly shaken Lucas" as they were "the only two who were present in the house".
He said the pair, who had been living together at Ms Irvine's grandmother's house in Lancaster at the time of the incident, had lied "from the very, very start" and changed their stories about what had happened to Lucas upon arrest.
"The prosecution submit that for both of them to tell so many lies from the very start is a clear sign that they were in this together," he said.
However, he said that "none of the accounts given by the defendants account for those injuries".
Mr Watson also told the jury of two previous incidents which Lucas had suffered in the months leading up to his death which had not been thought to be "significant" at the time by doctors.
He said the baby had been taken to hospital with a shoulder injury in August 2010, which Ms Irvine had said was caused by him "grabbing" restraining straps in his pram as he was lifted out.
A second injury, a graze to Lucas' head, was said by Ms Irvine to have been the result of him falling from a "faulty" pram, the court heard.
Mr Watson said though the explanations were "inconceivable", doctors had not thought the injuries to be non-accidental at the time.
The case continues.