Mexican federal police arrested alleged member of the Zetas drug cartel, Jose Guadalupe "El Sasi" Reyes Rivera, on Tuesday. Reyes Rivera is thought to be the mastermind of the brutal massacre of 72 mostly Central American immigrants in San Fernando, Tamaulipas, in 2010. The massacre was only discovered by the Mexican Army after one man lived to tell the tale. Three months ago, Mexico's Attorney General officially recognized that police also participated in the San Fernando massacre as well in the murders of 193 people found in clandestine graves in April, 2011. Clayton Conn reports from Mexico City for teleSUR