Mexican authorities discovered 12 bodies in 11 clandestine graves in Chihuahua state, near the U.S. border, during searches conducted from December 18 to 20.

The remains were sent to forensic labs in Ciudad Juarez for identification and cause-of-death analysis. Such graves are commonly used by drug cartels and kidnapping gangs to dispose of victims.

Chihuahua, plagued by organized crime violence, has recorded nearly 4,000 missing persons since 1952, contributing to Mexico’s broader crisis of around 120,000 missing people, CBS News has reported.

Written by B.C. Begley