It is not yet clear how the baby, understood to be less than three weeks old, sustained his injuries.
Detective Inspector Gary Lendrum said the investigation into the newborn's death was ongoing.
"The baby was taken to hospital on Tuesday 23 May 2017 in a critical condition and sadly passed away on the Friday," he said.
"At this stage, police are treating the death as suspicious however we still have a number of inquiries to make.
"Police are awaiting the results of forensic testing and this is expected to take a significant amount of time."
Lendrum said he could not make any further comment on the boy's death until he received those results.