Police have released CCTV footage showing killer Sharyar Ali at a casino while baby Hunter Patrick McGleenon sat alone outside in a car - hours before he murdered the 11-month-old.
Ali, who admitted murdering baby Hunter, has been told he will serve a minimum of 13 years in jail.
The 34-year-old of Westenra Terrace in Monaghan, had claimed that the infant had fallen off a low sofa and struck his head on a concrete floor.
On Thursday, police released footage showing the killer in the hours before he committed his crime.
Detective Inspector Mark Gibson said: "Sharyar Ali was in a relationship with Hunter's mother, and had been entrusted to look after the baby at her home in Keady while she went to visit a sick relative.
"It was while she was away doing a good deed that the tragic event unfolded. Evidence gathered, which includes CCTV footage, shows Mr Ali's whereabouts later that day.
"In the afternoon, he drives from Keady, with Hunter in the car. Later from CCTV footage, we see him go into a casino in Castleblayney - he's gambling, losing money he remains in the casino for almost two-and-a-half hours while 11-month-old baby Hunter is left outside in the car, alone.
"This is on a cold November evening. It's later that night, however, having returned to the house in Keady, that Hunter's young life is taken.
"He dies from serious injuries, injuries inflicted by Sharyar Ali - the very person who should have been caring for and protecting him."
DI Gibson added: "He would later claim Hunter had sustained head injuries from a fall before subsequently admitting to murder.
"Today my thoughts are first and foremost with Hunter's loving mother and family."
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