The head of Mexico's immigration agency, Francisco Garduno, is under investigation over a deadly fire last month at a migrant detention center in the northern border city of Ciudad Juarez, President Andres Manuel Lopez Obrador said on Wednesday.
The Mexican attorney general's office said on Tuesday it had launched a probe against the heads of the National Migration Institute (INM), without giving their full names.
"There's an investigation which includes (Garduno) in the unfortunate case regarding the migrant lives lost in Ciudad Juarez, we still don't know how far-reaching it is, or what he is accused of," Lopez Obrador said in a regular news conference.
The fire, which authorities say began after one or more of the migrants set alight mattresses as a protest, claimed the lives of 40 male migrants, most of them from Central America.
Lopez Obrador said Tuesday the migrants were unable to escape from the facility located near the U.S. border because the person holding the key to their cell was absent.
A number of arrests, including INM agents and a private security guard, have already been made over the blaze.
(Reporting by Kylie Madry; Editing by Dave Graham)