UN Secretary-General Antonio Guterres appointed Dmitry Titov to lead a special investigation of the attack that killed 15 UN peacekeepers in the Democratic Republic of Congo last month and wounded 43 others.
The December 7 attack in the Beni territory of North Kivu province was one of the worst to target UN peacekeepers in recent history in the Democratic Republic of Congo.
Titov, a Russian national who has worked in UN peacekeeping, will also look into other attacks against peacekeepers in that area, a UN statement said.
"This special investigation will include a focus on the December 7 attack in Semuliki, in which 15 Tanzanian peacekeepers were killed, 43 wounded and one remains missing," it said.
The United Nations has said the ambush of the peacekeeping base was carried out by suspected Allied Democratic Forces (ADF) rebels, a shadowy group that is one of several armed groups active in the North Kivu region.
UN investigators will examine the circumstances surrounding the attacks, evaluate the response of the peacekeepers and make recommendations on how to prevent such violence, the UN said.
Two military officers from Tanzania will take part in the probe that will travel to the DR Congo later this month and to countries in the region.
The attack was the bloodiest against MONUSCO, the UN force deployed in the DR Congo since 1999, and the worst against a UN force since the death of 24 Pakistani peacekeepers in Somalia in June 1993.