Mr. Vance spent less than five years in the Silicon Valley tech sector, but the connections he made with Peter Thiel and others were crucial to his political rise.
The European Union has sanctioned settler extremists for "systematic human rights violations against Palestinians" and human rights groups say the Israeli military is complicit.
The Israeli military said it targeted militants operating in a UN school used as a shelter in Nuseirat. A second attack left casualties in Al-Mawasi, Gaza's Health Ministry said.
Jay Slater disappeared last month on the Spanish island of Tenerife. A missing persons group said Monday that a body and his belongings had been found.