A father has been jailed for at least 12 years for murdering his baby son.
David Christie, 36, shook six-week-old Marshall so violently he suffered multiple rib and catastrophic brain injuries.
The baby died of head injuries five days after the assault in Blackpool, Lancashire, on 10 March last year.
Detectives said he had previously suffered a brain injury and fractured ribs in Christie's care.
Christie was found guilty of murder at Preston Crown Court on Friday and was sentenced to life imprisonment with a minimum term 12 years.
North West Ambulance Service alerted police after being called to tend to Marshall at the family home in Wyre Grove.
The baby was taken by ambulance to Blackpool Victoria Hospital and then Royal Manchester Children's Hospital where he died on 15 March.
A post-mortem examination revealed he died of head injuries.
Christie claimed he unintentionally injured Marshall while trying resuscitate him after he collapsed at the family home.
He was initially charged with wounding but was charged with murder following the baby's death.
Det Insp Paddy O'Neill, of Lancashire Constabulary, said after sentencing: "In his short life, Marshall Christie should have been able to look to his father for the love and protection of a parent.
"My thoughts remain with Marshall and his family who have been put in an insufferable position by Christie's actions.
"I hope that this conviction can offer them some comfort as they try to move on with their lives."