In the video, the teen had a handgun and claimed to be a Palm Beach County resident. The police department said the teen - whose name has not been released and is believed to be a Canadian citizen - made an online video threat to shoot people at the LGBTQ event, which took place Sunday on Clematis Street in downtown West Palm Beach. West Palm Beach police said Monday a 17-year-old boy has been arrested in Canada for a mass shooting threat directed at 'Pride On the Block.'