Atuhaire revealed that the perpetrators did not use their sexual organs, which she described as a small mercy amid the violence.
Atuhaire, a Ugandan lawyer and journalist, also spoke at the briefing, revealing she was stripped naked, beaten, and sexually violated after refusing to undress.
She added that she was "screaming so hard" that they had to cover her mouth.
Mwangi publicly identified Faustin Mafwele, a Tanzanian official, as the officer who ordered the torture.
Boniface Mwangi received by his family at Wilson Airport after being airlifted from Nkunda where he had been dumped by Tanzanian authorities.