Judge murdered was involved in high-profile drug cases

A Mexican federal judge who presided over appeals from high-profile drug kingpins in recent years was fatally shot in the head outside his home on Monday, authorities said.

Judge Vicente Bermúdez handled several legal challenges lodged by lawyers for Joaquín "El Chapo" Guzmán, the jailed leader of the Sinaloa Cartel, as well Miguel Treviño, ex-leader of the Zetas cartel.

President Enrique Peña Nieto said in a televised speech on Monday that he ordered his attorney general to investigate the murder, but he did not provide additional information about the case.

Since March, Bermúdez served as a judge overseeing legal challenges and federal trials in the state of Mexico just outside the capital, where Mexico's maximum security Altiplano prison is located.

Treviño is a prisoner at the Altiplano facility, and Guzmán is in a Ciudad Juárez prison, across the border from El Paso, Texas, awaiting extradition to the United States.

Guzmán's lawyers have filed numerous legal challenges aimed at preventing his extradition, but government officials have said it is likely he will be sent to the United States by early 2017.