Detectives have charged a 31-year-old man with murder following the death of 11-month-old Hunter McGleenon in Keady.
He has also been charged with possession of an indecent photograph of a child and illegal entry to the UK.
A post mortem into the death of Hunter McGleenon, was completed on Thursday.
In a statement earlier on Friday, Detective Chief Inspector Eamonn Corrigan said: “Sadly, following the results of the post mortem, I can confirm I am now treating this as a murder investigation.
“My thoughts remain with Hunter’s family and loved ones who are coming to terms with their devastating loss.
"This is something no parent should ever have to experience. His family should be looking forward to Hunter’s second Christmas."
The 31-year-old man is due to appear at Newry Magistrates' Court on Saturday.