A man has been charged with murder over the death of a three-month-old baby boy more than three years ago.

A WA Police spokeswoman confirmed homicide squad officers charged Wayne William Downing, 47, over the 2016 death of Noah Jayde Downing on Wednesday.

Wayne Downing. Credit:Facebook

Police said the baby died from inflicted injuries in May 2016 and a long running investigation into his death is ongoing.

Mr Downing lives in Lockridge and was arrested earlier this week. It is understood Mr Downing was the baby's grandfather.