A Calgary man has been charged with second-degree murder more than a year after the death of his three-month-old son.

Emergency crews were called to a home in the 100 block of Atlanta Crescent S.E. at about 12:30 p.m. on April 25, 2018 for reports of an infant in medical distress, police said in a release Monday.

The unconscious baby was rushed to hospital, where he died two days later.

Because the information the father provided medical staff was inconsistent with the symptoms the infant was showing, the Calgary Police Service's child abuse unit was notified.

The child had been alone with his father when the incident happened.

"Following a complex investigation, police believe the child died from injuries that were not accidental," the release said.

"Investigations into the death of children can take longer than other investigations because of the specialized expertise and tests needed to collect and interpret medical evidence."

The infant's father, Anthony Karl Kurucz, 29, of Calgary, is charged with one count of second-degree murder.

He was scheduled to appear in court Monday.

Police are not releasing the name of the infant as it would identify the mother, who is not a suspect.

Investigators will release more information about the case on Tuesday.

The investigation is still ongoing and anyone with information is asked to contact the homicide line at 403-428-8877, the CPS non-emergency line at 403-266-1234, or Crime Stoppers at 1-800-222-8477.