GENEVA — The president of the United Nations Human Rights Council on Monday named a former New York judge to be the third member of a three-person panel established to investigate possible international law violations by Israel and Hamas in the Gaza conflict.

The council president, Baudelaire Ndong Ella, picked Mary McGowan Davis, a legal consultant who retired in 1998 as a Supreme Court justice in New York State and worked as a Legal Aid Society lawyer and an assistant federal prosecutor. She joins a panel led by Prof. William Schabas, a Canadian expert on international law. The other member is Doudou Diène, a lawyer from Senegal who has served as a United Nations special rapporteur on racism.

The panel’s investigation, set up by a Palestinian-sponsored resolution in a Human Rights Council session at the end of July, is scheduled to report back in March 2015. In a statement to that session, the top United Nations human rights official, Navi Pillay, condemned Hamas rocket attacks on Israel and Israel’s military assaults on Gaza. She asserted that the high number of Palestinian deaths belied Israel’s claim that all necessary precautions had been taken to protect civilian lives.

Israel has denounced the inquiry, describing it as a “kangaroo court” incapable of impartial deliberations, and has said it will conduct its own investigation.