The police officer shot and killed in the Jersey City mass shooting Tuesday was meeting a confidential informant at a cemetery before he encountered the two attackers in a stolen U-Haul van, a senior law enforcement official told PIX 11. Authorities have been investigating why Detective Joseph Seals was in the cemetery, and discovered he was meeting an informant connected to one of his gun or narcotics cases, according to the official. PIX 11 reports the meeting was not connected to the mass shooting suspects David Anderson and Francine Graham, who allegedly ambushed Seals when he approached the van. Police said Anderson and Graham had previously posted anti-Semitic and anti-police statements on social media before they drove to the Jersey City Kosher Market a few blocks away from the cemetery and killed three others in the store. The shooting is now being investigated as an act of domestic terrorism, according to authorities.