OCCUPIED JERUSALEM — The Israeli military said on Monday that it was investigating a video that appears to show an Israeli army sniper shooting a motionless Palestinian across the border in Gaza, to whoops of excitement from the onlooker. Israeli television channels broadcast the clip at the start of their primetime evening news bulletins — with one host describing it as disturbing — after it circulated widely on social networks. Its release comes after more than a week of daily protests by Palestinians at the Gaza-Israel border in which 30 Gazans have been shot dead. However, the Israeli military said that the clip might have been filmed months ago. The amateur-