MEXICO CITY (AP) — A Mexican judge ordered that three Mexican immigration officials, a private security guard and a Venezuelan migrant be held for investigation in connection with a fire last week at an immigration detention center in northern Mexico that killed 40 migrants.

The four people responsible for security at the Ciudad Juarez facility will be held on charges of homicide by omission and causing injuries, while the migrant who allegedly set the fire faces charges of homicide and causing injuries, Mexico’s Federal Judiciary Council said after Tuesday’s hearing.

A video from a security camera inside the facility shows guards walking away when the fire started last Monday night inside the cell holding migrants and not making any attempt to release them. It was not clear whether those guards had keys to the cell doors.

More than two dozen migrants were seriously injured in the fire.