A corrections lieutenant at the Brooklyn Detention Center was made to drop his pants by federal agents after he bragged about his unusual penis while attacking female inmates.
Three of Eugenio Perez's five victims gave matching descriptions of the guard's penis and told investigators of the nickname he had given it.
Investigators were able to identify Perez from the victims descriptions and had a search warrant to see the penis themselves.
Perez, 46, and Carlos Richard Martinez, 47, were charged with several sexual attacks and face life in prison after appearing to have turned the detention center in to their own violent sex den, the New York Post reports.
Martinez was responsible for educating the staff on PREA (Prison Rape Elimination Act) but reportedly posted a photo of himself with a prison employee on Facebook with the caption "It's only PREA when you don't like it."
The guards used their rank to threaten inmates with extra prison time if they told authorities of the attacks.
At least one is accused of threatening the women with solitary confinement unless they complied.
A third guard, Armando Moronta, 39, faces 60 years in prison for repeatedly having sex with three inmates at the facility.