Authorities arrested three suspects on Monday in connection with the death of a Mexican migration agent found earlier that day showing no signs of life, according to state security and migration officials.

The incident marks a rare case of lethal violence against migration officials, occurring just weeks ahead of an anticipated immigration crackdown as U.S. President-elect Donald Trump prepares to take office.

State investigators reported that the agent had sustained a fatal head injury, with his body showing "signs of violence," according to a statement from Chihuahua's public security office.

Authorities apprehended two Venezuelan men and later detained a Colombian national, the National Institute of Migration (INM) confirmed in a separate statement.

The attack took place at a checkpoint near Ciudad Juárez, just south of the U.S. border city of El Paso, Texas. The agent was assaulted after requesting identification documents from a group of foreign nationals, INM said.

The incident unfolds as heightened anxiety grips would-be migrants, who fear stricter U.S. entry policies following Trump’s return to power on January 20.

Meanwhile, hundreds of migrants gathered in long lines outside an immigration office in southern Mexico on Monday, seeking documentation to travel safely northward and legally enter the U.S. before the expected policy shift.