The twin brothers from Chicago are reviled by Mexican cartels but praised by prosecutors as the most valuable traffickers-turned-informants in recent U.S. history.

Pedro and Margarito Flores will be sentenced Tuesday at federal court in their hometown amid tight security.

They pleaded guilty at a secret 2012 hearing to running a nearly $2 billion U.S. trafficking franchise. Their partners included Mexican drug lord Joaquin "El Chapo" Guzman.

The risk of reprisals to them and anyone associated with them is so great that even their lawyer's name has been kept secret.

Prosecutors are requesting a remarkably lenient prison term of around 10 years. They say it's reward for cooperation that led to indictments of Guzman and 50 others. With time served, they could be out within a few years.