had to be selective in choosing the men willing to commit such a gruesome
crime. He chose the soon-to-be-murderers based on their past actions;
those who by now had no problem killing anyone Trujillo ordered were chosen.
These men were Victor Alicinio Peņa Rivera, Trujillo's right-hand man,
and some members of his secret police force, Ciriaco de la Rosa, Ramon
Emilio Rojas, Alfonso Cruz Valeria, and Emilio Estrada Malleta. The secret
police, called the Military Intelligence Service (Servicio de Inteligencia
Militar, or SIM), had been organized by Trujillo back when he was still
making his way up the army ranks. His experience with the U.S. Marines
had taught him about military intelligence, and he had formed various
agencies that would spy on the Dominican people, as well as on each other.
Dominican citizens had to carry identification cards issued by the secret
mafia-like disappearances of Trujillo's critics as well as rumors of tortures
and killings carried out by the SIM earned them a fearful reputation throughout
the island. The participation of the aforementioned assassins in SIM activities
led to them being chosen to carry out the murder of the Mirabal sisters.