A device containing nails, chemicals and ball bearings which “had the potential to explode and injure many people or kill them” was thrown into an Invasion Day rally in Perth by a 31-year-old man on Monday, WA Police allege. Police have charged the man with one count of unlawful act or omission with intent to harm (endangering life, health or safety of any person) and one count of making or possession of explosives under suspicious circumstances, while releasing CCTV footage that appears to depict an object being thrown into the 2,500-strong crowd.