police are investigating suspected arson attacks on three melbourne churches with links to paedophile priests .
firefighters were called to st mary 's , dandenong , at 2 am on april 1 .
the church is said to be the site of child sex attacks perpetrated by now-deceased father kevin o'donnell .
police have released an image of ` a man that may be able to assist with their enquiries '
comes after two separate suspicious blazes were lit on march 30 .